docs: def color(x, y):
      """triangles.
  
      Colors:
      - http://paletton.com/#uid=70l150klllletuehUpNoMgTsdcs shade 2
      """
  
      if (x-4) > (y-4) and -(y-4) <= (x-4):
          # right
          return "#CDB95B"
      elif (x-4) > (y-4) and -(y-4) > (x-4):
          # top
          return "#CD845B"
      elif (x-4) <= (y-4) and -(y-4) <= (x-4):
          # bottom
          return "#57488E"
      elif (x-4) <= (y-4) and -(y-4) > (x-4):
          # left
          return "#3B8772"
  
      # should not happen
      return "black"