docs: def hilbertrot(n, x, y, rx, ry):
      """Rotates and flips a quadrant appropriately for the Hilbert scan
      generator. See https://en.wikipedia.org/wiki/Hilbert_curve.
      """
      if ry == 0:
          if rx == 1:
              x = n - 1 - x
              y = n - 1 - y
          return y, x
      return x, y