+-------+
          |   g   |
          | green |
          |       |
  +-------+-------+-------+-------+
  |   p   |   g   |   p   |   y   |
  |purple | green |purple |yellow |
  |       |       |       |       |
  +-------+-------+-------+-------+
          |   r   |
          |  red  |
          |       |
          +-------+