b a x b a y 0 0 0 0 1 1 0 1 0 0 1 1 0 1 2 0 1 0 0 0 1 3 0 1 1 1 1 1 4 1 0 0 0 0 1 5 1 0 1 1 1 0 6 1 1 0 1 0 1 7 1 1 1 0 1 1