1 2 3 4 5 6 7 8 9
| in | sel | a | b | c | d | | 0 | 00 | 0 | 0 | 0 | 0 | | 0 | 01 | 0 | 0 | 0 | 0 | | 0 | 10 | 0 | 0 | 0 | 0 | | 0 | 11 | 0 | 0 | 0 | 0 | | 1 | 00 | 1 | 0 | 0 | 0 | | 1 | 01 | 0 | 1 | 0 | 0 | | 1 | 10 | 0 | 0 | 1 | 0 | | 1 | 11 | 0 | 0 | 0 | 1 |