+---+     +---+
| F | <## | A |
+---+     +---+
  #         #
  #         #
  v         v
+---+     +---+
| G |     | B |
+---+     +---+
  #         #
  #         #
  v         v
+---+     +---+
| H |     | C |
+---+     +---+
  #         #
  #         #
  v         v
+---+     +---+
| I |     | D |
+---+     +---+
            #
            #
            v
          +---+
          | E |
          +---+