b := (x and a) or (b and a) or (x and b)
a := (not b and not a and not x) or (a and x) or (b and a)
y := (b and not a and x) or (b and a and not x)
bax bay
1 000 010
2 001 000
3 010 000
4 011 110
5 100 000
6 101 101
7 110 111
8 111 110