docs: def into2dBlocks(arr, n0, n1):
      """
      similar to blockshaped
      but splits an array into n0*n1 blocks
      """
      s0, s1 = arr.shape
      b = blockshaped(arr, s0// n0, s1// n1)
      return b.reshape(n0, n1, *b.shape[1:])