Here is an example of the OR of the four convex right corners:
0000000000000000 0000000000000000 0000000011111000 0011110011111100 0011110011111000 0111111111111000 0011111111110000 0011000001111000 0011000001111000 0001000001111000 0011111111110000 0011111111100000 0011111111000000 0011111110000000 0000000000000000 0000000000000000Before |
0000000000000000 0000000000000000 0000000010001000 0010010000000000 0000000000000000 0000000000001000 0000000000000000 0000000000001000 0010000000000000 0000000000001000 0010000000010000 0000000000100000 0000000001000000 0010000010000000 0000000000000000 0000000000000000After |