[
    [1,1,1,1],
    [2,2,2,2],
    [3,3,3,3],
    [4,4,4,4],
]

[
    [2, 1, -5, 1],
    [1, -3, 0, -6],
    [0, 2, -1, 2],
    [1, 4, -7, 6]
]