8
2
4
+ 1 1 x
+ 2 1 y
1  0 0 0 pat00
1  0 1 1 pat01
1  1 1 0 pat11
1  1 0 1 pat10
0  0 0 0 tpat00
0  0 1 1 tpat01
0  1 1 0 tpat11
0  1 0 1 tpat10
