x x 8 1 x x 5 x x
9 6 x x 8 x x x x
x 5 x x 3 6 x 9 8
x x 7 x 6 9 x 1 2
x x 6 8 x 7 3 x x
8 1 x 4 5 x 6 x x
4 2 x 6 7 x x 8 x
x x x x 4 x x 6 3
x x 5 x x 8 7 x x