A B
B A
---
1 0 1 0 1 0 1 0 1
0 0 0 0 0 0 0 0 0
1 0 1 1 1 1 1 0 1
0 0 1 1 1 1 1 0 0
1 0 1 1 1 1 1 0 1
0 0 1 1 1 1 1 0 0
1 0 1 A 1 1 1 0 1
B 0 0 0 0 0 0 0 0
1 1 0 0 1 0 1 0 1
1 1 0 0 1 1 1 1 1
