const boxes = {
  0: [[0, 0], [0, 1], [0, 2],
  [1, 0], [1, 1], [1, 2],
  [2, 0], [2, 1], [2, 2]],

  1: [[0, 3], [0, 4], [0, 5],
  [1, 3], [1, 4], [1, 5],
  [2, 3], [2, 4], [2, 5]],

  2: [[0, 6], [0, 7], [0, 8],
  [1, 6], [1, 7], [1, 8],
  [2, 6], [2, 7], [2, 8]],

  3: [[3, 0], [3, 1], [3, 2],
  [4, 0], [4, 1], [4, 2],
  [5, 0], [5, 1], [5, 2]],

  4: [[3, 3], [3, 4], [3, 5],
  [4, 3], [4, 4], [4, 5],
  [5, 3], [5, 4], [5, 5]],

  5: [[3, 6], [3, 7], [3, 8],
  [4, 6], [4, 7], [4, 8],
  [5, 6], [5, 7], [5, 8]],

  6: [[6, 0], [6, 1], [6, 2],
  [7, 0], [7, 1], [7, 2],
  [8, 0], [8, 1], [8, 2]],

  7: [[6, 3], [6, 4], [6, 5],
  [7, 3], [7, 4], [7, 5],
  [8, 3], [8, 4], [8, 5]],

  8: [[6, 6], [6, 7], [6, 8],
  [7, 6], [7, 7], [7, 8],
  [8, 6], [8, 7], [8, 8]]
};