CHECKER 4 4 [0,0,-1,1,0,2] [2,0,1,1,2,2] [1,1,1,3,2,2] [3,1,3,3,4,2] [0,2,0,4,1,3] [2,2,2,4,3,3] [1,3,0,4,1,5] [3,3,2,4,3,5]