CHECKER 4 4 [0,0,1,0,-1,0] [1,0,0,1,2,1] [2,0,3,0,1,0] [3,0,2,1,4,1] [0,1,1,1,-1,1] [1,1,0,2,2,2] [2,1,3,1,1,1] [3,1,2,2,4,2] [0,2,-1,3,0,3] [2,2,1,3,3,3] [0,3,1,3,0,4] [1,3,0,4,2,4] [3,3,4,3,2,4]