[
  [[1, 7], [2, 6], [3, 5], [0, 4]],
  [[2, 1], [3, 7], [4, 6], [0, 5]],
  [[3, 2], [4, 1], [5, 7], [0, 6]],
  [[4, 3], [5, 2], [6, 1], [0, 7]],
  [[5, 4], [6, 3], [7, 2], [0, 1]],
  [[6, 5], [7, 4], [1, 3], [0, 2]],
  [[7, 6], [1, 5], [2, 4], [0, 3]],
]
[
  [undef, 4, 5, 6, 0 .. 3],
  [4, undef, 1, 5, 2, 6, 3, 0],
  [5, 1, undef, 2, 6, 3, 0, 4],
  [6, 5, 2, undef, 3, 0, 4, 1],
  [0, 2, 6, 3, undef, 4, 1, 5],
  [1, 6, 3, 0, 4, undef, 5, 2],
  [2, 3, 0, 4, 1, 5, undef, 6],
  [3, 0, 4, 1, 5, 2, 6],
]