[1, 0, 0, 0, 2, 0, 0, 0]
[1, 2, 1, 0, 2, 0, 0, 0]
[1, 2, 1,-2, 0, 0, 2, 1, -2, 0, 0, 0]
[1, 2]
[2, 1]