21 files changed, 6386 insertions, 0 deletions
diff --git a/projects/10/ArrayTest/Main.jack b/projects/10/ArrayTest/Main.jack
new file mode 100644
index 0000000..aa237b1
--- /dev/null
+++ b/projects/10/ArrayTest/Main.jack
@@ -0,0 +1,38 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/10/ArrayTest/Main.jack
+
+// (identical to projects/09/Average/Main.jack)
+
+/** Computes the average of a sequence of integers. */
+class Main {
+    function void main() {
+        var Array a;
+        var int length;
+        var int i, sum;
+	
+	let length = Keyboard.readInt("HOW MANY NUMBERS? ");
+	let a = Array.new(length);
+	let i = 0;
+	
+	while (i < length) {
+	    let a[i] = Keyboard.readInt("ENTER THE NEXT NUMBER: ");
+	    let i = i + 1;
+	}
+	
+	let i = 0;
+	let sum = 0;
+	
+	while (i < length) {
+	    let sum = sum + a[i];
+	    let i = i + 1;
+	}
+	
+	do Output.printString("THE AVERAGE IS: ");
+	do Output.printInt(sum / length);
+	do Output.println();
+	
+	return;
+    }
+}
diff --git a/projects/10/ArrayTest/Main.xml b/projects/10/ArrayTest/Main.xml
new file mode 100644
index 0000000..0ea96df
--- /dev/null
+++ b/projects/10/ArrayTest/Main.xml
@@ -0,0 +1,286 @@
+<class>
+  <keyword> class </keyword>
+  <identifier> Main </identifier>
+  <symbol> { </symbol>
+  <subroutineDec>
+    <keyword> function </keyword>
+    <keyword> void </keyword>
+    <identifier> main </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <varDec>
+        <keyword> var </keyword>
+        <identifier> Array </identifier>
+        <identifier> a </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <varDec>
+        <keyword> var </keyword>
+        <keyword> int </keyword>
+        <identifier> length </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <varDec>
+        <keyword> var </keyword>
+        <keyword> int </keyword>
+        <identifier> i </identifier>
+        <symbol> , </symbol>
+        <identifier> sum </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> length </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Keyboard </identifier>
+              <symbol> . </symbol>
+              <identifier> readInt </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <stringConstant> HOW MANY NUMBERS?  </stringConstant>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> a </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Array </identifier>
+              <symbol> . </symbol>
+              <identifier> new </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> length </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> i </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <integerConstant> 0 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <whileStatement>
+          <keyword> while </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> i </identifier>
+            </term>
+            <symbol> &lt; </symbol>
+            <term>
+              <identifier> length </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> a </identifier>
+              <symbol> [ </symbol>
+              <expression>
+                <term>
+                  <identifier> i </identifier>
+                </term>
+              </expression>
+              <symbol> ] </symbol>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> Keyboard </identifier>
+                  <symbol> . </symbol>
+                  <identifier> readInt </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                    <expression>
+                      <term>
+                        <stringConstant> ENTER THE NEXT NUMBER:  </stringConstant>
+                      </term>
+                    </expression>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> i </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> i </identifier>
+                </term>
+                <symbol> + </symbol>
+                <term>
+                  <integerConstant> 1 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+          </statements>
+          <symbol> } </symbol>
+        </whileStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> i </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <integerConstant> 0 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> sum </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <integerConstant> 0 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <whileStatement>
+          <keyword> while </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> i </identifier>
+            </term>
+            <symbol> &lt; </symbol>
+            <term>
+              <identifier> length </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> sum </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> sum </identifier>
+                </term>
+                <symbol> + </symbol>
+                <term>
+                  <identifier> a </identifier>
+                  <symbol> [ </symbol>
+                  <expression>
+                    <term>
+                      <identifier> i </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ] </symbol>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> i </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> i </identifier>
+                </term>
+                <symbol> + </symbol>
+                <term>
+                  <integerConstant> 1 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+          </statements>
+          <symbol> } </symbol>
+        </whileStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Output </identifier>
+          <symbol> . </symbol>
+          <identifier> printString </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <stringConstant> THE AVERAGE IS:  </stringConstant>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Output </identifier>
+          <symbol> . </symbol>
+          <identifier> printInt </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> sum </identifier>
+              </term>
+              <symbol> / </symbol>
+              <term>
+                <identifier> length </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Output </identifier>
+          <symbol> . </symbol>
+          <identifier> println </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <symbol> } </symbol>
+</class>
diff --git a/projects/10/ArrayTest/MainT.xml b/projects/10/ArrayTest/MainT.xml
new file mode 100644
index 0000000..68721ec
--- /dev/null
+++ b/projects/10/ArrayTest/MainT.xml
@@ -0,0 +1,142 @@
+<tokens>
+<keyword> class </keyword>
+<identifier> Main </identifier>
+<symbol> { </symbol>
+<keyword> function </keyword>
+<keyword> void </keyword>
+<identifier> main </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> var </keyword>
+<identifier> Array </identifier>
+<identifier> a </identifier>
+<symbol> ; </symbol>
+<keyword> var </keyword>
+<keyword> int </keyword>
+<identifier> length </identifier>
+<symbol> ; </symbol>
+<keyword> var </keyword>
+<keyword> int </keyword>
+<identifier> i </identifier>
+<symbol> , </symbol>
+<identifier> sum </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> length </identifier>
+<symbol> = </symbol>
+<identifier> Keyboard </identifier>
+<symbol> . </symbol>
+<identifier> readInt </identifier>
+<symbol> ( </symbol>
+<stringConstant> HOW MANY NUMBERS?  </stringConstant>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> a </identifier>
+<symbol> = </symbol>
+<identifier> Array </identifier>
+<symbol> . </symbol>
+<identifier> new </identifier>
+<symbol> ( </symbol>
+<identifier> length </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> i </identifier>
+<symbol> = </symbol>
+<integerConstant> 0 </integerConstant>
+<symbol> ; </symbol>
+<keyword> while </keyword>
+<symbol> ( </symbol>
+<identifier> i </identifier>
+<symbol> &lt; </symbol>
+<identifier> length </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> a </identifier>
+<symbol> [ </symbol>
+<identifier> i </identifier>
+<symbol> ] </symbol>
+<symbol> = </symbol>
+<identifier> Keyboard </identifier>
+<symbol> . </symbol>
+<identifier> readInt </identifier>
+<symbol> ( </symbol>
+<stringConstant> ENTER THE NEXT NUMBER:  </stringConstant>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> i </identifier>
+<symbol> = </symbol>
+<identifier> i </identifier>
+<symbol> + </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> let </keyword>
+<identifier> i </identifier>
+<symbol> = </symbol>
+<integerConstant> 0 </integerConstant>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> sum </identifier>
+<symbol> = </symbol>
+<integerConstant> 0 </integerConstant>
+<symbol> ; </symbol>
+<keyword> while </keyword>
+<symbol> ( </symbol>
+<identifier> i </identifier>
+<symbol> &lt; </symbol>
+<identifier> length </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> sum </identifier>
+<symbol> = </symbol>
+<identifier> sum </identifier>
+<symbol> + </symbol>
+<identifier> a </identifier>
+<symbol> [ </symbol>
+<identifier> i </identifier>
+<symbol> ] </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> i </identifier>
+<symbol> = </symbol>
+<identifier> i </identifier>
+<symbol> + </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> do </keyword>
+<identifier> Output </identifier>
+<symbol> . </symbol>
+<identifier> printString </identifier>
+<symbol> ( </symbol>
+<stringConstant> THE AVERAGE IS:  </stringConstant>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Output </identifier>
+<symbol> . </symbol>
+<identifier> printInt </identifier>
+<symbol> ( </symbol>
+<identifier> sum </identifier>
+<symbol> / </symbol>
+<identifier> length </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Output </identifier>
+<symbol> . </symbol>
+<identifier> println </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+</tokens>
diff --git a/projects/10/ExpressionLessSquare/Main.jack b/projects/10/ExpressionLessSquare/Main.jack
new file mode 100644
index 0000000..94764ad
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/Main.jack
@@ -0,0 +1,28 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/10/ExpressionLessSquare/Main.jack
+
+/** Expressionless version of projects/10/Square/Main.jack. */
+
+class Main {
+    static boolean test;    // Added for testing -- there is no static keyword
+                            // in the Square files.
+
+    function void main() {
+        var SquareGame game;
+        let game = game;
+        do game.run();
+        do game.dispose();
+        return;
+    }
+
+    function void more() {  // Added to test Jack syntax that is not used in
+        var boolean b;      // the Square files.
+        if (b) {
+        }
+        else {              // There is no else keyword in the Square files.
+        }
+        return;
+    }
+}
diff --git a/projects/10/ExpressionLessSquare/Main.xml b/projects/10/ExpressionLessSquare/Main.xml
new file mode 100644
index 0000000..f71a0ef
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/Main.xml
@@ -0,0 +1,114 @@
+<class>
+  <keyword> class </keyword>
+  <identifier> Main </identifier>
+  <symbol> { </symbol>
+  <classVarDec>
+    <keyword> static </keyword>
+    <keyword> boolean </keyword>
+    <identifier> test </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <subroutineDec>
+    <keyword> function </keyword>
+    <keyword> void </keyword>
+    <identifier> main </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <varDec>
+        <keyword> var </keyword>
+        <identifier> SquareGame </identifier>
+        <identifier> game </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> game </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> game </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> game </identifier>
+          <symbol> . </symbol>
+          <identifier> run </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> game </identifier>
+          <symbol> . </symbol>
+          <identifier> dispose </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> function </keyword>
+    <keyword> void </keyword>
+    <identifier> more </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <varDec>
+        <keyword> var </keyword>
+        <keyword> boolean </keyword>
+        <identifier> b </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> b </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+          </statements>
+          <symbol> } </symbol>
+          <keyword> else </keyword>
+          <symbol> { </symbol>
+          <statements>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <symbol> } </symbol>
+</class>
diff --git a/projects/10/ExpressionLessSquare/MainT.xml b/projects/10/ExpressionLessSquare/MainT.xml
new file mode 100644
index 0000000..441dfed
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/MainT.xml
@@ -0,0 +1,64 @@
+<tokens>
+<keyword> class </keyword>
+<identifier> Main </identifier>
+<symbol> { </symbol>
+<keyword> static </keyword>
+<keyword> boolean </keyword>
+<identifier> test </identifier>
+<symbol> ; </symbol>
+<keyword> function </keyword>
+<keyword> void </keyword>
+<identifier> main </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> var </keyword>
+<identifier> SquareGame </identifier>
+<identifier> game </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> game </identifier>
+<symbol> = </symbol>
+<identifier> game </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> game </identifier>
+<symbol> . </symbol>
+<identifier> run </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> game </identifier>
+<symbol> . </symbol>
+<identifier> dispose </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> function </keyword>
+<keyword> void </keyword>
+<identifier> more </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> var </keyword>
+<keyword> boolean </keyword>
+<identifier> b </identifier>
+<symbol> ; </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> b </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<symbol> } </symbol>
+<keyword> else </keyword>
+<symbol> { </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+</tokens>
diff --git a/projects/10/ExpressionLessSquare/Square.jack b/projects/10/ExpressionLessSquare/Square.jack
new file mode 100644
index 0000000..33a54ad
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/Square.jack
@@ -0,0 +1,99 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+/// File name: projects/10/ExpressionLessSquare/Square.jack
+
+/** Expressionless version of projects/10/Square/Square.jack. */
+
+class Square {
+
+   field int x, y; 
+   field int size; 
+
+   constructor Square new(int Ax, int Ay, int Asize) {
+      let x = Ax;
+      let y = Ay;
+      let size = Asize;
+      do draw();
+      return x;
+   }
+
+   method void dispose() {
+      do Memory.deAlloc(this);
+      return;
+   }
+
+   method void draw() {
+      do Screen.setColor(x);
+      do Screen.drawRectangle(x, y, x, y);
+      return;
+   }
+
+   method void erase() {
+      do Screen.setColor(x);
+      do Screen.drawRectangle(x, y, x, y);
+      return;
+   }
+
+   method void incSize() {
+      if (x) {
+         do erase();
+         let size = size;
+         do draw();
+      }
+      return;
+   }
+
+   method void decSize() {
+      if (size) {
+         do erase();
+         let size = size;
+         do draw();
+      }
+      return;
+   }
+
+   method void moveUp() {
+      if (y) {
+         do Screen.setColor(x);
+         do Screen.drawRectangle(x, y, x, y);
+         let y = y;
+         do Screen.setColor(x);
+         do Screen.drawRectangle(x, y, x, y);
+      }
+      return;
+   }
+
+   method void moveDown() {
+      if (y) {
+         do Screen.setColor(x);
+         do Screen.drawRectangle(x, y, x, y);
+         let y = y;
+         do Screen.setColor(x);
+         do Screen.drawRectangle(x, y, x, y);
+      }
+      return;
+   }
+
+   method void moveLeft() {
+      if (x) {
+         do Screen.setColor(x);
+         do Screen.drawRectangle(x, y, x, y);
+         let x = x;
+         do Screen.setColor(x);
+         do Screen.drawRectangle(x, y, x, y);
+      }
+      return;
+   }
+
+   method void moveRight() {
+      if (x) {
+         do Screen.setColor(x);
+         do Screen.drawRectangle(x, y, x, y);
+         let x = x;
+         do Screen.setColor(x);
+         do Screen.drawRectangle(x, y, x, y);
+      }
+      return;
+   }
+}  
diff --git a/projects/10/ExpressionLessSquare/Square.xml b/projects/10/ExpressionLessSquare/Square.xml
new file mode 100644
index 0000000..ed0e6ec
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/Square.xml
@@ -0,0 +1,967 @@
+<class>
+  <keyword> class </keyword>
+  <identifier> Square </identifier>
+  <symbol> { </symbol>
+  <classVarDec>
+    <keyword> field </keyword>
+    <keyword> int </keyword>
+    <identifier> x </identifier>
+    <symbol> , </symbol>
+    <identifier> y </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <classVarDec>
+    <keyword> field </keyword>
+    <keyword> int </keyword>
+    <identifier> size </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <subroutineDec>
+    <keyword> constructor </keyword>
+    <identifier> Square </identifier>
+    <identifier> new </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+      <keyword> int </keyword>
+      <identifier> Ax </identifier>
+      <symbol> , </symbol>
+      <keyword> int </keyword>
+      <identifier> Ay </identifier>
+      <symbol> , </symbol>
+      <keyword> int </keyword>
+      <identifier> Asize </identifier>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> x </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Ax </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> y </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Ay </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> size </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Asize </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> draw </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <expression>
+            <term>
+              <identifier> x </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> dispose </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Memory </identifier>
+          <symbol> . </symbol>
+          <identifier> deAlloc </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <keyword> this </keyword>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> draw </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Screen </identifier>
+          <symbol> . </symbol>
+          <identifier> setColor </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Screen </identifier>
+          <symbol> . </symbol>
+          <identifier> drawRectangle </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> y </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> y </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> erase </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Screen </identifier>
+          <symbol> . </symbol>
+          <identifier> setColor </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Screen </identifier>
+          <symbol> . </symbol>
+          <identifier> drawRectangle </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> y </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> y </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> incSize </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> x </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> erase </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> size </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> size </identifier>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> draw </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> decSize </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> size </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> erase </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> size </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> size </identifier>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> draw </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveUp </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> y </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> y </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> y </identifier>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveDown </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> y </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> y </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> y </identifier>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveLeft </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> x </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> x </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> x </identifier>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveRight </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> x </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> x </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> x </identifier>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <symbol> } </symbol>
+</class>
diff --git a/projects/10/ExpressionLessSquare/SquareGame.jack b/projects/10/ExpressionLessSquare/SquareGame.jack
new file mode 100644
index 0000000..2866f0d
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/SquareGame.jack
@@ -0,0 +1,60 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/10/ExpressionLessSquare/SquareGame.jack
+
+/** Expressionless version of projects/10/Square/SquareGame.jack. */
+
+class SquareGame {
+   field Square square; 
+   field int direction; 
+
+   constructor SquareGame new() {
+      let square = square;
+      let direction = direction;
+      return square;
+   }
+
+   method void dispose() {
+      do square.dispose();
+      do Memory.deAlloc(square);
+      return;
+   }
+
+   method void moveSquare() {
+      if (direction) { do square.moveUp(); }
+      if (direction) { do square.moveDown(); }
+      if (direction) { do square.moveLeft(); }
+      if (direction) { do square.moveRight(); }
+      do Sys.wait(direction);
+      return;
+   }
+
+   method void run() {
+      var char key;
+      var boolean exit;
+      
+      let exit = key;
+      while (exit) {
+         while (key) {
+            let key = key;
+            do moveSquare();
+         }
+
+         if (key) { let exit = exit; }
+         if (key) { do square.decSize(); }
+         if (key) { do square.incSize(); }
+         if (key) { let direction = exit; }
+         if (key) { let direction = key; }
+         if (key) { let direction = square; }
+         if (key) { let direction = direction; }
+
+         while (key) {
+            let key = key;
+            do moveSquare();
+         }
+      }
+      return;
+    }
+}
+
diff --git a/projects/10/ExpressionLessSquare/SquareGame.xml b/projects/10/ExpressionLessSquare/SquareGame.xml
new file mode 100644
index 0000000..288c6cd
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/SquareGame.xml
@@ -0,0 +1,544 @@
+<class>
+  <keyword> class </keyword>
+  <identifier> SquareGame </identifier>
+  <symbol> { </symbol>
+  <classVarDec>
+    <keyword> field </keyword>
+    <identifier> Square </identifier>
+    <identifier> square </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <classVarDec>
+    <keyword> field </keyword>
+    <keyword> int </keyword>
+    <identifier> direction </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <subroutineDec>
+    <keyword> constructor </keyword>
+    <identifier> SquareGame </identifier>
+    <identifier> new </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> square </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> square </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> direction </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <expression>
+            <term>
+              <identifier> square </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> dispose </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> square </identifier>
+          <symbol> . </symbol>
+          <identifier> dispose </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Memory </identifier>
+          <symbol> . </symbol>
+          <identifier> deAlloc </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> square </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveSquare </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> square </identifier>
+              <symbol> . </symbol>
+              <identifier> moveUp </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> square </identifier>
+              <symbol> . </symbol>
+              <identifier> moveDown </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> square </identifier>
+              <symbol> . </symbol>
+              <identifier> moveLeft </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> square </identifier>
+              <symbol> . </symbol>
+              <identifier> moveRight </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Sys </identifier>
+          <symbol> . </symbol>
+          <identifier> wait </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> direction </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> run </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <varDec>
+        <keyword> var </keyword>
+        <keyword> char </keyword>
+        <identifier> key </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <varDec>
+        <keyword> var </keyword>
+        <keyword> boolean </keyword>
+        <identifier> exit </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> exit </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> key </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <whileStatement>
+          <keyword> while </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> exit </identifier>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <whileStatement>
+              <keyword> while </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> key </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> key </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+                <doStatement>
+                  <keyword> do </keyword>
+                  <identifier> moveSquare </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                  <symbol> ; </symbol>
+                </doStatement>
+              </statements>
+              <symbol> } </symbol>
+            </whileStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> exit </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> exit </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <doStatement>
+                  <keyword> do </keyword>
+                  <identifier> square </identifier>
+                  <symbol> . </symbol>
+                  <identifier> decSize </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                  <symbol> ; </symbol>
+                </doStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <doStatement>
+                  <keyword> do </keyword>
+                  <identifier> square </identifier>
+                  <symbol> . </symbol>
+                  <identifier> incSize </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                  <symbol> ; </symbol>
+                </doStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> direction </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> exit </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> direction </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> key </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> direction </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> square </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> direction </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> direction </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <whileStatement>
+              <keyword> while </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> key </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> key </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+                <doStatement>
+                  <keyword> do </keyword>
+                  <identifier> moveSquare </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                  <symbol> ; </symbol>
+                </doStatement>
+              </statements>
+              <symbol> } </symbol>
+            </whileStatement>
+          </statements>
+          <symbol> } </symbol>
+        </whileStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <symbol> } </symbol>
+</class>
diff --git a/projects/10/ExpressionLessSquare/SquareGameT.xml b/projects/10/ExpressionLessSquare/SquareGameT.xml
new file mode 100644
index 0000000..278a8a9
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/SquareGameT.xml
@@ -0,0 +1,268 @@
+<tokens>
+<keyword> class </keyword>
+<identifier> SquareGame </identifier>
+<symbol> { </symbol>
+<keyword> field </keyword>
+<identifier> Square </identifier>
+<identifier> square </identifier>
+<symbol> ; </symbol>
+<keyword> field </keyword>
+<keyword> int </keyword>
+<identifier> direction </identifier>
+<symbol> ; </symbol>
+<keyword> constructor </keyword>
+<identifier> SquareGame </identifier>
+<identifier> new </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> square </identifier>
+<symbol> = </symbol>
+<identifier> square </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<identifier> direction </identifier>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<identifier> square </identifier>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> dispose </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> dispose </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Memory </identifier>
+<symbol> . </symbol>
+<identifier> deAlloc </identifier>
+<symbol> ( </symbol>
+<identifier> square </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveSquare </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> moveUp </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> moveDown </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> moveLeft </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> moveRight </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> do </keyword>
+<identifier> Sys </identifier>
+<symbol> . </symbol>
+<identifier> wait </identifier>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> run </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> var </keyword>
+<keyword> char </keyword>
+<identifier> key </identifier>
+<symbol> ; </symbol>
+<keyword> var </keyword>
+<keyword> boolean </keyword>
+<identifier> exit </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> exit </identifier>
+<symbol> = </symbol>
+<identifier> key </identifier>
+<symbol> ; </symbol>
+<keyword> while </keyword>
+<symbol> ( </symbol>
+<identifier> exit </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> while </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<identifier> key </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> moveSquare </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> exit </identifier>
+<symbol> = </symbol>
+<identifier> exit </identifier>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> decSize </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> incSize </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<identifier> exit </identifier>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<identifier> key </identifier>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<identifier> square </identifier>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<identifier> direction </identifier>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> while </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<identifier> key </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> moveSquare </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+</tokens>
diff --git a/projects/10/ExpressionLessSquare/SquareT.xml b/projects/10/ExpressionLessSquare/SquareT.xml
new file mode 100644
index 0000000..cd03a1e
--- /dev/null
+++ b/projects/10/ExpressionLessSquare/SquareT.xml
@@ -0,0 +1,449 @@
+<tokens>
+<keyword> class </keyword>
+<identifier> Square </identifier>
+<symbol> { </symbol>
+<keyword> field </keyword>
+<keyword> int </keyword>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ; </symbol>
+<keyword> field </keyword>
+<keyword> int </keyword>
+<identifier> size </identifier>
+<symbol> ; </symbol>
+<keyword> constructor </keyword>
+<identifier> Square </identifier>
+<identifier> new </identifier>
+<symbol> ( </symbol>
+<keyword> int </keyword>
+<identifier> Ax </identifier>
+<symbol> , </symbol>
+<keyword> int </keyword>
+<identifier> Ay </identifier>
+<symbol> , </symbol>
+<keyword> int </keyword>
+<identifier> Asize </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> x </identifier>
+<symbol> = </symbol>
+<identifier> Ax </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> y </identifier>
+<symbol> = </symbol>
+<identifier> Ay </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> size </identifier>
+<symbol> = </symbol>
+<identifier> Asize </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> draw </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<identifier> x </identifier>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> dispose </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Memory </identifier>
+<symbol> . </symbol>
+<identifier> deAlloc </identifier>
+<symbol> ( </symbol>
+<keyword> this </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> draw </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> erase </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> incSize </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> erase </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> size </identifier>
+<symbol> = </symbol>
+<identifier> size </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> draw </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> decSize </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> erase </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> size </identifier>
+<symbol> = </symbol>
+<identifier> size </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> draw </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveUp </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> y </identifier>
+<symbol> = </symbol>
+<identifier> y </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveDown </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> y </identifier>
+<symbol> = </symbol>
+<identifier> y </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveLeft </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> x </identifier>
+<symbol> = </symbol>
+<identifier> x </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveRight </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> x </identifier>
+<symbol> = </symbol>
+<identifier> x </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+</tokens>
diff --git a/projects/10/Square/Main.jack b/projects/10/Square/Main.jack
new file mode 100644
index 0000000..a6fd2c2
--- /dev/null
+++ b/projects/10/Square/Main.jack
@@ -0,0 +1,36 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/10/Square/Main.jack
+
+// (derived from projects/09/Square/Main.jack, with testing additions)
+
+/** Initializes a new Square Dance game and starts running it. */
+class Main {
+    static boolean test;    // Added for testing -- there is no static keyword
+                            // in the Square files.
+    function void main() {
+      var SquareGame game;
+      let game = SquareGame.new();
+      do game.run();
+      do game.dispose();
+      return;
+    }
+
+    function void more() {  // Added to test Jack syntax that is not used in
+        var int i, j;       // the Square files.
+        var String s;
+        var Array a;
+        if (false) {
+            let s = "string constant";
+            let s = null;
+            let a[1] = a[2];
+        }
+        else {              // There is no else keyword in the Square files.
+            let i = i * (-j);
+            let j = j / (-2);   // note: unary negate constant 2
+            let i = i | j;
+        }
+        return;
+    }
+}
diff --git a/projects/10/Square/Main.xml b/projects/10/Square/Main.xml
new file mode 100644
index 0000000..8796fa9
--- /dev/null
+++ b/projects/10/Square/Main.xml
@@ -0,0 +1,244 @@
+<class>
+  <keyword> class </keyword>
+  <identifier> Main </identifier>
+  <symbol> { </symbol>
+  <classVarDec>
+    <keyword> static </keyword>
+    <keyword> boolean </keyword>
+    <identifier> test </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <subroutineDec>
+    <keyword> function </keyword>
+    <keyword> void </keyword>
+    <identifier> main </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <varDec>
+        <keyword> var </keyword>
+        <identifier> SquareGame </identifier>
+        <identifier> game </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> game </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> SquareGame </identifier>
+              <symbol> . </symbol>
+              <identifier> new </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> game </identifier>
+          <symbol> . </symbol>
+          <identifier> run </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> game </identifier>
+          <symbol> . </symbol>
+          <identifier> dispose </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> function </keyword>
+    <keyword> void </keyword>
+    <identifier> more </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <varDec>
+        <keyword> var </keyword>
+        <keyword> int </keyword>
+        <identifier> i </identifier>
+        <symbol> , </symbol>
+        <identifier> j </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <varDec>
+        <keyword> var </keyword>
+        <identifier> String </identifier>
+        <identifier> s </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <varDec>
+        <keyword> var </keyword>
+        <identifier> Array </identifier>
+        <identifier> a </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <keyword> false </keyword>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> s </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <stringConstant> string constant </stringConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> s </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <keyword> null </keyword>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> a </identifier>
+              <symbol> [ </symbol>
+              <expression>
+                <term>
+                  <integerConstant> 1 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ] </symbol>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> a </identifier>
+                  <symbol> [ </symbol>
+                  <expression>
+                    <term>
+                      <integerConstant> 2 </integerConstant>
+                    </term>
+                  </expression>
+                  <symbol> ] </symbol>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+          </statements>
+          <symbol> } </symbol>
+          <keyword> else </keyword>
+          <symbol> { </symbol>
+          <statements>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> i </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> i </identifier>
+                </term>
+                <symbol> * </symbol>
+                <term>
+                  <symbol> ( </symbol>
+                  <expression>
+                    <term>
+                      <symbol> - </symbol>
+                      <term>
+                        <identifier> j </identifier>
+                      </term>
+                    </term>
+                  </expression>
+                  <symbol> ) </symbol>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> j </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> j </identifier>
+                </term>
+                <symbol> / </symbol>
+                <term>
+                  <symbol> ( </symbol>
+                  <expression>
+                    <term>
+                      <symbol> - </symbol>
+                      <term>
+                        <integerConstant> 2 </integerConstant>
+                      </term>
+                    </term>
+                  </expression>
+                  <symbol> ) </symbol>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> i </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> i </identifier>
+                </term>
+                <symbol> | </symbol>
+                <term>
+                  <identifier> j </identifier>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <symbol> } </symbol>
+</class>
diff --git a/projects/10/Square/MainT.xml b/projects/10/Square/MainT.xml
new file mode 100644
index 0000000..bc92200
--- /dev/null
+++ b/projects/10/Square/MainT.xml
@@ -0,0 +1,126 @@
+<tokens>
+<keyword> class </keyword>
+<identifier> Main </identifier>
+<symbol> { </symbol>
+<keyword> static </keyword>
+<keyword> boolean </keyword>
+<identifier> test </identifier>
+<symbol> ; </symbol>
+<keyword> function </keyword>
+<keyword> void </keyword>
+<identifier> main </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> var </keyword>
+<identifier> SquareGame </identifier>
+<identifier> game </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> game </identifier>
+<symbol> = </symbol>
+<identifier> SquareGame </identifier>
+<symbol> . </symbol>
+<identifier> new </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> game </identifier>
+<symbol> . </symbol>
+<identifier> run </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> game </identifier>
+<symbol> . </symbol>
+<identifier> dispose </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> function </keyword>
+<keyword> void </keyword>
+<identifier> more </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> var </keyword>
+<keyword> int </keyword>
+<identifier> i </identifier>
+<symbol> , </symbol>
+<identifier> j </identifier>
+<symbol> ; </symbol>
+<keyword> var </keyword>
+<identifier> String </identifier>
+<identifier> s </identifier>
+<symbol> ; </symbol>
+<keyword> var </keyword>
+<identifier> Array </identifier>
+<identifier> a </identifier>
+<symbol> ; </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<keyword> false </keyword>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> s </identifier>
+<symbol> = </symbol>
+<stringConstant> string constant </stringConstant>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> s </identifier>
+<symbol> = </symbol>
+<keyword> null </keyword>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> a </identifier>
+<symbol> [ </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ] </symbol>
+<symbol> = </symbol>
+<identifier> a </identifier>
+<symbol> [ </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ] </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> else </keyword>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> i </identifier>
+<symbol> = </symbol>
+<identifier> i </identifier>
+<symbol> * </symbol>
+<symbol> ( </symbol>
+<symbol> - </symbol>
+<identifier> j </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> j </identifier>
+<symbol> = </symbol>
+<identifier> j </identifier>
+<symbol> / </symbol>
+<symbol> ( </symbol>
+<symbol> - </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> i </identifier>
+<symbol> = </symbol>
+<identifier> i </identifier>
+<symbol> | </symbol>
+<identifier> j </identifier>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+</tokens>
diff --git a/projects/10/Square/Square.jack b/projects/10/Square/Square.jack
new file mode 100644
index 0000000..3faf24f
--- /dev/null
+++ b/projects/10/Square/Square.jack
@@ -0,0 +1,110 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/10/Square/Square.jack
+
+// (same as projects/09/Square/Square.jack)
+
+/** Implements a graphical square. */
+class Square {
+
+   field int x, y; // screen location of the square's top-left corner
+   field int size; // length of this square, in pixels
+
+   /** Constructs a new square with a given location and size. */
+   constructor Square new(int Ax, int Ay, int Asize) {
+      let x = Ax;
+      let y = Ay;
+      let size = Asize;
+      do draw();
+      return this;
+   }
+
+   /** Disposes this square. */
+   method void dispose() {
+      do Memory.deAlloc(this);
+      return;
+   }
+
+   /** Draws the square on the screen. */
+   method void draw() {
+      do Screen.setColor(true);
+      do Screen.drawRectangle(x, y, x + size, y + size);
+      return;
+   }
+
+   /** Erases the square from the screen. */
+   method void erase() {
+      do Screen.setColor(false);
+      do Screen.drawRectangle(x, y, x + size, y + size);
+      return;
+   }
+
+    /** Increments the square size by 2 pixels. */
+   method void incSize() {
+      if (((y + size) < 254) & ((x + size) < 510)) {
+         do erase();
+         let size = size + 2;
+         do draw();
+      }
+      return;
+   }
+
+   /** Decrements the square size by 2 pixels. */
+   method void decSize() {
+      if (size > 2) {
+         do erase();
+         let size = size - 2;
+         do draw();
+      }
+      return;
+   }
+
+   /** Moves the square up by 2 pixels. */
+   method void moveUp() {
+      if (y > 1) {
+         do Screen.setColor(false);
+         do Screen.drawRectangle(x, (y + size) - 1, x + size, y + size);
+         let y = y - 2;
+         do Screen.setColor(true);
+         do Screen.drawRectangle(x, y, x + size, y + 1);
+      }
+      return;
+   }
+
+   /** Moves the square down by 2 pixels. */
+   method void moveDown() {
+      if ((y + size) < 254) {
+         do Screen.setColor(false);
+         do Screen.drawRectangle(x, y, x + size, y + 1);
+         let y = y + 2;
+         do Screen.setColor(true);
+         do Screen.drawRectangle(x, (y + size) - 1, x + size, y + size);
+      }
+      return;
+   }
+
+   /** Moves the square left by 2 pixels. */
+   method void moveLeft() {
+      if (x > 1) {
+         do Screen.setColor(false);
+         do Screen.drawRectangle((x + size) - 1, y, x + size, y + size);
+         let x = x - 2;
+         do Screen.setColor(true);
+         do Screen.drawRectangle(x, y, x + 1, y + size);
+      }
+      return;
+   }
+
+   /** Moves the square right by 2 pixels. */
+   method void moveRight() {
+      if ((x + size) < 510) {
+         do Screen.setColor(false);
+         do Screen.drawRectangle(x, y, x + 1, y + size);
+         let x = x + 2;
+         do Screen.setColor(true);
+         do Screen.drawRectangle((x + size) - 1, y, x + size, y + size);
+      }
+      return;
+   }
+}
diff --git a/projects/10/Square/Square.xml b/projects/10/Square/Square.xml
new file mode 100644
index 0000000..ff5f235
--- /dev/null
+++ b/projects/10/Square/Square.xml
@@ -0,0 +1,1211 @@
+<class>
+  <keyword> class </keyword>
+  <identifier> Square </identifier>
+  <symbol> { </symbol>
+  <classVarDec>
+    <keyword> field </keyword>
+    <keyword> int </keyword>
+    <identifier> x </identifier>
+    <symbol> , </symbol>
+    <identifier> y </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <classVarDec>
+    <keyword> field </keyword>
+    <keyword> int </keyword>
+    <identifier> size </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <subroutineDec>
+    <keyword> constructor </keyword>
+    <identifier> Square </identifier>
+    <identifier> new </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+      <keyword> int </keyword>
+      <identifier> Ax </identifier>
+      <symbol> , </symbol>
+      <keyword> int </keyword>
+      <identifier> Ay </identifier>
+      <symbol> , </symbol>
+      <keyword> int </keyword>
+      <identifier> Asize </identifier>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> x </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Ax </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> y </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Ay </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> size </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Asize </identifier>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> draw </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <expression>
+            <term>
+              <keyword> this </keyword>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> dispose </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Memory </identifier>
+          <symbol> . </symbol>
+          <identifier> deAlloc </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <keyword> this </keyword>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> draw </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Screen </identifier>
+          <symbol> . </symbol>
+          <identifier> setColor </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <keyword> true </keyword>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Screen </identifier>
+          <symbol> . </symbol>
+          <identifier> drawRectangle </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> y </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+              <symbol> + </symbol>
+              <term>
+                <identifier> size </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> y </identifier>
+              </term>
+              <symbol> + </symbol>
+              <term>
+                <identifier> size </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> erase </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Screen </identifier>
+          <symbol> . </symbol>
+          <identifier> setColor </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <keyword> false </keyword>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Screen </identifier>
+          <symbol> . </symbol>
+          <identifier> drawRectangle </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> y </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> x </identifier>
+              </term>
+              <symbol> + </symbol>
+              <term>
+                <identifier> size </identifier>
+              </term>
+            </expression>
+            <symbol> , </symbol>
+            <expression>
+              <term>
+                <identifier> y </identifier>
+              </term>
+              <symbol> + </symbol>
+              <term>
+                <identifier> size </identifier>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> incSize </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <symbol> ( </symbol>
+                  <expression>
+                    <term>
+                      <identifier> y </identifier>
+                    </term>
+                    <symbol> + </symbol>
+                    <term>
+                      <identifier> size </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ) </symbol>
+                </term>
+                <symbol> &lt; </symbol>
+                <term>
+                  <integerConstant> 254 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+            </term>
+            <symbol> &amp; </symbol>
+            <term>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <symbol> ( </symbol>
+                  <expression>
+                    <term>
+                      <identifier> x </identifier>
+                    </term>
+                    <symbol> + </symbol>
+                    <term>
+                      <identifier> size </identifier>
+                    </term>
+                  </expression>
+                  <symbol> ) </symbol>
+                </term>
+                <symbol> &lt; </symbol>
+                <term>
+                  <integerConstant> 510 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> erase </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> size </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> size </identifier>
+                </term>
+                <symbol> + </symbol>
+                <term>
+                  <integerConstant> 2 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> draw </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> decSize </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> size </identifier>
+            </term>
+            <symbol> &gt; </symbol>
+            <term>
+              <integerConstant> 2 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> erase </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> size </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> size </identifier>
+                </term>
+                <symbol> - </symbol>
+                <term>
+                  <integerConstant> 2 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> draw </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveUp </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> y </identifier>
+            </term>
+            <symbol> &gt; </symbol>
+            <term>
+              <integerConstant> 1 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <keyword> false </keyword>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <symbol> ( </symbol>
+                    <expression>
+                      <term>
+                        <identifier> y </identifier>
+                      </term>
+                      <symbol> + </symbol>
+                      <term>
+                        <identifier> size </identifier>
+                      </term>
+                    </expression>
+                    <symbol> ) </symbol>
+                  </term>
+                  <symbol> - </symbol>
+                  <term>
+                    <integerConstant> 1 </integerConstant>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> y </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> y </identifier>
+                </term>
+                <symbol> - </symbol>
+                <term>
+                  <integerConstant> 2 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <keyword> true </keyword>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <integerConstant> 1 </integerConstant>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveDown </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> y </identifier>
+                </term>
+                <symbol> + </symbol>
+                <term>
+                  <identifier> size </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+            </term>
+            <symbol> &lt; </symbol>
+            <term>
+              <integerConstant> 254 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <keyword> false </keyword>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <integerConstant> 1 </integerConstant>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> y </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> y </identifier>
+                </term>
+                <symbol> + </symbol>
+                <term>
+                  <integerConstant> 2 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <keyword> true </keyword>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <symbol> ( </symbol>
+                    <expression>
+                      <term>
+                        <identifier> y </identifier>
+                      </term>
+                      <symbol> + </symbol>
+                      <term>
+                        <identifier> size </identifier>
+                      </term>
+                    </expression>
+                    <symbol> ) </symbol>
+                  </term>
+                  <symbol> - </symbol>
+                  <term>
+                    <integerConstant> 1 </integerConstant>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveLeft </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> x </identifier>
+            </term>
+            <symbol> &gt; </symbol>
+            <term>
+              <integerConstant> 1 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <keyword> false </keyword>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <symbol> ( </symbol>
+                    <expression>
+                      <term>
+                        <identifier> x </identifier>
+                      </term>
+                      <symbol> + </symbol>
+                      <term>
+                        <identifier> size </identifier>
+                      </term>
+                    </expression>
+                    <symbol> ) </symbol>
+                  </term>
+                  <symbol> - </symbol>
+                  <term>
+                    <integerConstant> 1 </integerConstant>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> x </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> x </identifier>
+                </term>
+                <symbol> - </symbol>
+                <term>
+                  <integerConstant> 2 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <keyword> true </keyword>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <integerConstant> 1 </integerConstant>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveRight </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> x </identifier>
+                </term>
+                <symbol> + </symbol>
+                <term>
+                  <identifier> size </identifier>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+            </term>
+            <symbol> &lt; </symbol>
+            <term>
+              <integerConstant> 510 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <keyword> false </keyword>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <integerConstant> 1 </integerConstant>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <letStatement>
+              <keyword> let </keyword>
+              <identifier> x </identifier>
+              <symbol> = </symbol>
+              <expression>
+                <term>
+                  <identifier> x </identifier>
+                </term>
+                <symbol> + </symbol>
+                <term>
+                  <integerConstant> 2 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ; </symbol>
+            </letStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> setColor </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <keyword> true </keyword>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> Screen </identifier>
+              <symbol> . </symbol>
+              <identifier> drawRectangle </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <symbol> ( </symbol>
+                    <expression>
+                      <term>
+                        <identifier> x </identifier>
+                      </term>
+                      <symbol> + </symbol>
+                      <term>
+                        <identifier> size </identifier>
+                      </term>
+                    </expression>
+                    <symbol> ) </symbol>
+                  </term>
+                  <symbol> - </symbol>
+                  <term>
+                    <integerConstant> 1 </integerConstant>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> x </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <identifier> y </identifier>
+                  </term>
+                  <symbol> + </symbol>
+                  <term>
+                    <identifier> size </identifier>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <symbol> } </symbol>
+</class>
diff --git a/projects/10/Square/SquareGame.jack b/projects/10/Square/SquareGame.jack
new file mode 100644
index 0000000..4f71b16
--- /dev/null
+++ b/projects/10/Square/SquareGame.jack
@@ -0,0 +1,81 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/10/Square/SquareGame.jack
+
+// (same as projects/09/Square/SquareGame.jack)
+
+/**
+ * Implements the Square Dance game.
+ * This simple game allows the user to move a black square around
+ * the screen, and change the square's size during the movement.
+ * When the game starts, a square of 30 by 30 pixels is shown at the
+ * top-left corner of the screen. The user controls the square as follows.
+ * The 4 arrow keys are used to move the square up, down, left, and right.
+ * The 'z' and 'x' keys are used, respectively, to decrement and increment
+ * the square's size. The 'q' key is used to quit the game.
+ */
+
+class SquareGame {
+   field Square square; // the square of this game
+   field int direction; // the square's current direction: 
+                        // 0=none, 1=up, 2=down, 3=left, 4=right
+
+   /** Constructs a new Square Game. */
+   constructor SquareGame new() {
+      // Creates a 30 by 30 pixels square and positions it at the top-left
+      // of the screen.
+      let square = Square.new(0, 0, 30);
+      let direction = 0;  // initial state is no movement
+      return this;
+   }
+
+   /** Disposes this game. */
+   method void dispose() {
+      do square.dispose();
+      do Memory.deAlloc(this);
+      return;
+   }
+
+   /** Moves the square in the current direction. */
+   method void moveSquare() {
+      if (direction = 1) { do square.moveUp(); }
+      if (direction = 2) { do square.moveDown(); }
+      if (direction = 3) { do square.moveLeft(); }
+      if (direction = 4) { do square.moveRight(); }
+      do Sys.wait(5);  // delays the next movement
+      return;
+   }
+
+   /** Runs the game: handles the user's inputs and moves the square accordingly */
+   method void run() {
+      var char key;  // the key currently pressed by the user
+      var boolean exit;
+      let exit = false;
+      
+      while (~exit) {
+         // waits for a key to be pressed
+         while (key = 0) {
+            let key = Keyboard.keyPressed();
+            do moveSquare();
+         }
+         if (key = 81)  { let exit = true; }     // q key
+         if (key = 90)  { do square.decSize(); } // z key
+         if (key = 88)  { do square.incSize(); } // x key
+         if (key = 131) { let direction = 1; }   // up arrow
+         if (key = 133) { let direction = 2; }   // down arrow
+         if (key = 130) { let direction = 3; }   // left arrow
+         if (key = 132) { let direction = 4; }   // right arrow
+
+         // waits for the key to be released
+         while (~(key = 0)) {
+            let key = Keyboard.keyPressed();
+            do moveSquare();
+         }
+     } // while
+     return;
+   }
+}
+
+
+
diff --git a/projects/10/Square/SquareGame.xml b/projects/10/Square/SquareGame.xml
new file mode 100644
index 0000000..ed3ab6e
--- /dev/null
+++ b/projects/10/Square/SquareGame.xml
@@ -0,0 +1,643 @@
+<class>
+  <keyword> class </keyword>
+  <identifier> SquareGame </identifier>
+  <symbol> { </symbol>
+  <classVarDec>
+    <keyword> field </keyword>
+    <identifier> Square </identifier>
+    <identifier> square </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <classVarDec>
+    <keyword> field </keyword>
+    <keyword> int </keyword>
+    <identifier> direction </identifier>
+    <symbol> ; </symbol>
+  </classVarDec>
+  <subroutineDec>
+    <keyword> constructor </keyword>
+    <identifier> SquareGame </identifier>
+    <identifier> new </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> square </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <identifier> Square </identifier>
+              <symbol> . </symbol>
+              <identifier> new </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+                <expression>
+                  <term>
+                    <integerConstant> 0 </integerConstant>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <integerConstant> 0 </integerConstant>
+                  </term>
+                </expression>
+                <symbol> , </symbol>
+                <expression>
+                  <term>
+                    <integerConstant> 30 </integerConstant>
+                  </term>
+                </expression>
+              </expressionList>
+              <symbol> ) </symbol>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> direction </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <integerConstant> 0 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <expression>
+            <term>
+              <keyword> this </keyword>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> dispose </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> square </identifier>
+          <symbol> . </symbol>
+          <identifier> dispose </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Memory </identifier>
+          <symbol> . </symbol>
+          <identifier> deAlloc </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <keyword> this </keyword>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> moveSquare </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <statements>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+            <symbol> = </symbol>
+            <term>
+              <integerConstant> 1 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> square </identifier>
+              <symbol> . </symbol>
+              <identifier> moveUp </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+            <symbol> = </symbol>
+            <term>
+              <integerConstant> 2 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> square </identifier>
+              <symbol> . </symbol>
+              <identifier> moveDown </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+            <symbol> = </symbol>
+            <term>
+              <integerConstant> 3 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> square </identifier>
+              <symbol> . </symbol>
+              <identifier> moveLeft </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <ifStatement>
+          <keyword> if </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <identifier> direction </identifier>
+            </term>
+            <symbol> = </symbol>
+            <term>
+              <integerConstant> 4 </integerConstant>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <doStatement>
+              <keyword> do </keyword>
+              <identifier> square </identifier>
+              <symbol> . </symbol>
+              <identifier> moveRight </identifier>
+              <symbol> ( </symbol>
+              <expressionList>
+              </expressionList>
+              <symbol> ) </symbol>
+              <symbol> ; </symbol>
+            </doStatement>
+          </statements>
+          <symbol> } </symbol>
+        </ifStatement>
+        <doStatement>
+          <keyword> do </keyword>
+          <identifier> Sys </identifier>
+          <symbol> . </symbol>
+          <identifier> wait </identifier>
+          <symbol> ( </symbol>
+          <expressionList>
+            <expression>
+              <term>
+                <integerConstant> 5 </integerConstant>
+              </term>
+            </expression>
+          </expressionList>
+          <symbol> ) </symbol>
+          <symbol> ; </symbol>
+        </doStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <subroutineDec>
+    <keyword> method </keyword>
+    <keyword> void </keyword>
+    <identifier> run </identifier>
+    <symbol> ( </symbol>
+    <parameterList>
+    </parameterList>
+    <symbol> ) </symbol>
+    <subroutineBody>
+      <symbol> { </symbol>
+      <varDec>
+        <keyword> var </keyword>
+        <keyword> char </keyword>
+        <identifier> key </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <varDec>
+        <keyword> var </keyword>
+        <keyword> boolean </keyword>
+        <identifier> exit </identifier>
+        <symbol> ; </symbol>
+      </varDec>
+      <statements>
+        <letStatement>
+          <keyword> let </keyword>
+          <identifier> exit </identifier>
+          <symbol> = </symbol>
+          <expression>
+            <term>
+              <keyword> false </keyword>
+            </term>
+          </expression>
+          <symbol> ; </symbol>
+        </letStatement>
+        <whileStatement>
+          <keyword> while </keyword>
+          <symbol> ( </symbol>
+          <expression>
+            <term>
+              <symbol> ~ </symbol>
+              <term>
+                <identifier> exit </identifier>
+              </term>
+            </term>
+          </expression>
+          <symbol> ) </symbol>
+          <symbol> { </symbol>
+          <statements>
+            <whileStatement>
+              <keyword> while </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+                <symbol> = </symbol>
+                <term>
+                  <integerConstant> 0 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> key </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> Keyboard </identifier>
+                      <symbol> . </symbol>
+                      <identifier> keyPressed </identifier>
+                      <symbol> ( </symbol>
+                      <expressionList>
+                      </expressionList>
+                      <symbol> ) </symbol>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+                <doStatement>
+                  <keyword> do </keyword>
+                  <identifier> moveSquare </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                  <symbol> ; </symbol>
+                </doStatement>
+              </statements>
+              <symbol> } </symbol>
+            </whileStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+                <symbol> = </symbol>
+                <term>
+                  <integerConstant> 81 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> exit </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <keyword> true </keyword>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+                <symbol> = </symbol>
+                <term>
+                  <integerConstant> 90 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <doStatement>
+                  <keyword> do </keyword>
+                  <identifier> square </identifier>
+                  <symbol> . </symbol>
+                  <identifier> decSize </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                  <symbol> ; </symbol>
+                </doStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+                <symbol> = </symbol>
+                <term>
+                  <integerConstant> 88 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <doStatement>
+                  <keyword> do </keyword>
+                  <identifier> square </identifier>
+                  <symbol> . </symbol>
+                  <identifier> incSize </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                  <symbol> ; </symbol>
+                </doStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+                <symbol> = </symbol>
+                <term>
+                  <integerConstant> 131 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> direction </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <integerConstant> 1 </integerConstant>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+                <symbol> = </symbol>
+                <term>
+                  <integerConstant> 133 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> direction </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <integerConstant> 2 </integerConstant>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+                <symbol> = </symbol>
+                <term>
+                  <integerConstant> 130 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> direction </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <integerConstant> 3 </integerConstant>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <ifStatement>
+              <keyword> if </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <identifier> key </identifier>
+                </term>
+                <symbol> = </symbol>
+                <term>
+                  <integerConstant> 132 </integerConstant>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> direction </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <integerConstant> 4 </integerConstant>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+              </statements>
+              <symbol> } </symbol>
+            </ifStatement>
+            <whileStatement>
+              <keyword> while </keyword>
+              <symbol> ( </symbol>
+              <expression>
+                <term>
+                  <symbol> ~ </symbol>
+                  <term>
+                    <symbol> ( </symbol>
+                    <expression>
+                      <term>
+                        <identifier> key </identifier>
+                      </term>
+                      <symbol> = </symbol>
+                      <term>
+                        <integerConstant> 0 </integerConstant>
+                      </term>
+                    </expression>
+                    <symbol> ) </symbol>
+                  </term>
+                </term>
+              </expression>
+              <symbol> ) </symbol>
+              <symbol> { </symbol>
+              <statements>
+                <letStatement>
+                  <keyword> let </keyword>
+                  <identifier> key </identifier>
+                  <symbol> = </symbol>
+                  <expression>
+                    <term>
+                      <identifier> Keyboard </identifier>
+                      <symbol> . </symbol>
+                      <identifier> keyPressed </identifier>
+                      <symbol> ( </symbol>
+                      <expressionList>
+                      </expressionList>
+                      <symbol> ) </symbol>
+                    </term>
+                  </expression>
+                  <symbol> ; </symbol>
+                </letStatement>
+                <doStatement>
+                  <keyword> do </keyword>
+                  <identifier> moveSquare </identifier>
+                  <symbol> ( </symbol>
+                  <expressionList>
+                  </expressionList>
+                  <symbol> ) </symbol>
+                  <symbol> ; </symbol>
+                </doStatement>
+              </statements>
+              <symbol> } </symbol>
+            </whileStatement>
+          </statements>
+          <symbol> } </symbol>
+        </whileStatement>
+        <returnStatement>
+          <keyword> return </keyword>
+          <symbol> ; </symbol>
+        </returnStatement>
+      </statements>
+      <symbol> } </symbol>
+    </subroutineBody>
+  </subroutineDec>
+  <symbol> } </symbol>
+</class>
diff --git a/projects/10/Square/SquareGameT.xml b/projects/10/Square/SquareGameT.xml
new file mode 100644
index 0000000..3136af2
--- /dev/null
+++ b/projects/10/Square/SquareGameT.xml
@@ -0,0 +1,315 @@
+<tokens>
+<keyword> class </keyword>
+<identifier> SquareGame </identifier>
+<symbol> { </symbol>
+<keyword> field </keyword>
+<identifier> Square </identifier>
+<identifier> square </identifier>
+<symbol> ; </symbol>
+<keyword> field </keyword>
+<keyword> int </keyword>
+<identifier> direction </identifier>
+<symbol> ; </symbol>
+<keyword> constructor </keyword>
+<identifier> SquareGame </identifier>
+<identifier> new </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> square </identifier>
+<symbol> = </symbol>
+<identifier> Square </identifier>
+<symbol> . </symbol>
+<identifier> new </identifier>
+<symbol> ( </symbol>
+<integerConstant> 0 </integerConstant>
+<symbol> , </symbol>
+<integerConstant> 0 </integerConstant>
+<symbol> , </symbol>
+<integerConstant> 30 </integerConstant>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 0 </integerConstant>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<keyword> this </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> dispose </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> dispose </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Memory </identifier>
+<symbol> . </symbol>
+<identifier> deAlloc </identifier>
+<symbol> ( </symbol>
+<keyword> this </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveSquare </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> moveUp </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> moveDown </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 3 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> moveLeft </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 4 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> moveRight </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> do </keyword>
+<identifier> Sys </identifier>
+<symbol> . </symbol>
+<identifier> wait </identifier>
+<symbol> ( </symbol>
+<integerConstant> 5 </integerConstant>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> run </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> var </keyword>
+<keyword> char </keyword>
+<identifier> key </identifier>
+<symbol> ; </symbol>
+<keyword> var </keyword>
+<keyword> boolean </keyword>
+<identifier> exit </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> exit </identifier>
+<symbol> = </symbol>
+<keyword> false </keyword>
+<symbol> ; </symbol>
+<keyword> while </keyword>
+<symbol> ( </symbol>
+<symbol> ~ </symbol>
+<identifier> exit </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> while </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 0 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<identifier> Keyboard </identifier>
+<symbol> . </symbol>
+<identifier> keyPressed </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> moveSquare </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 81 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> exit </identifier>
+<symbol> = </symbol>
+<keyword> true </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 90 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> decSize </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 88 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> square </identifier>
+<symbol> . </symbol>
+<identifier> incSize </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 131 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 133 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 130 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 3 </integerConstant>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 132 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> direction </identifier>
+<symbol> = </symbol>
+<integerConstant> 4 </integerConstant>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> while </keyword>
+<symbol> ( </symbol>
+<symbol> ~ </symbol>
+<symbol> ( </symbol>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<integerConstant> 0 </integerConstant>
+<symbol> ) </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> key </identifier>
+<symbol> = </symbol>
+<identifier> Keyboard </identifier>
+<symbol> . </symbol>
+<identifier> keyPressed </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> moveSquare </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+</tokens>
diff --git a/projects/10/Square/SquareT.xml b/projects/10/Square/SquareT.xml
new file mode 100644
index 0000000..69a8ca0
--- /dev/null
+++ b/projects/10/Square/SquareT.xml
@@ -0,0 +1,561 @@
+<tokens>
+<keyword> class </keyword>
+<identifier> Square </identifier>
+<symbol> { </symbol>
+<keyword> field </keyword>
+<keyword> int </keyword>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> ; </symbol>
+<keyword> field </keyword>
+<keyword> int </keyword>
+<identifier> size </identifier>
+<symbol> ; </symbol>
+<keyword> constructor </keyword>
+<identifier> Square </identifier>
+<identifier> new </identifier>
+<symbol> ( </symbol>
+<keyword> int </keyword>
+<identifier> Ax </identifier>
+<symbol> , </symbol>
+<keyword> int </keyword>
+<identifier> Ay </identifier>
+<symbol> , </symbol>
+<keyword> int </keyword>
+<identifier> Asize </identifier>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> let </keyword>
+<identifier> x </identifier>
+<symbol> = </symbol>
+<identifier> Ax </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> y </identifier>
+<symbol> = </symbol>
+<identifier> Ay </identifier>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> size </identifier>
+<symbol> = </symbol>
+<identifier> Asize </identifier>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> draw </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<keyword> this </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> dispose </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Memory </identifier>
+<symbol> . </symbol>
+<identifier> deAlloc </identifier>
+<symbol> ( </symbol>
+<keyword> this </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> draw </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> true </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> erase </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> false </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> incSize </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<symbol> ( </symbol>
+<symbol> ( </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> &lt; </symbol>
+<integerConstant> 254 </integerConstant>
+<symbol> ) </symbol>
+<symbol> &amp; </symbol>
+<symbol> ( </symbol>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> &lt; </symbol>
+<integerConstant> 510 </integerConstant>
+<symbol> ) </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> erase </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> size </identifier>
+<symbol> = </symbol>
+<identifier> size </identifier>
+<symbol> + </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> draw </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> decSize </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> size </identifier>
+<symbol> &gt; </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> erase </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> size </identifier>
+<symbol> = </symbol>
+<identifier> size </identifier>
+<symbol> - </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> draw </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveUp </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> y </identifier>
+<symbol> &gt; </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> false </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<symbol> ( </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> - </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> y </identifier>
+<symbol> = </symbol>
+<identifier> y </identifier>
+<symbol> - </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> true </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveDown </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<symbol> ( </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> &lt; </symbol>
+<integerConstant> 254 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> false </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> y </identifier>
+<symbol> = </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> true </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<symbol> ( </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> - </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveLeft </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> &gt; </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> false </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> - </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> x </identifier>
+<symbol> = </symbol>
+<identifier> x </identifier>
+<symbol> - </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> true </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> method </keyword>
+<keyword> void </keyword>
+<identifier> moveRight </identifier>
+<symbol> ( </symbol>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> if </keyword>
+<symbol> ( </symbol>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> &lt; </symbol>
+<integerConstant> 510 </integerConstant>
+<symbol> ) </symbol>
+<symbol> { </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> false </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> let </keyword>
+<identifier> x </identifier>
+<symbol> = </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<integerConstant> 2 </integerConstant>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> setColor </identifier>
+<symbol> ( </symbol>
+<keyword> true </keyword>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<keyword> do </keyword>
+<identifier> Screen </identifier>
+<symbol> . </symbol>
+<identifier> drawRectangle </identifier>
+<symbol> ( </symbol>
+<symbol> ( </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> - </symbol>
+<integerConstant> 1 </integerConstant>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> , </symbol>
+<identifier> x </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> , </symbol>
+<identifier> y </identifier>
+<symbol> + </symbol>
+<identifier> size </identifier>
+<symbol> ) </symbol>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<keyword> return </keyword>
+<symbol> ; </symbol>
+<symbol> } </symbol>
+<symbol> } </symbol>
+</tokens>