    +--+---+--+     +----+
    |  | C |  | --> | A1 |
    +--+---+--+     +----+
       |---+--+     +----+
       | D |  | --> | A2 |
        ---+--+     +----+
    +--+---+        +----+
    |  | E |    --> | A3 |
    +--+---+        +----+
       |---+        +----+
       | F |    --> | A4 |
        ---+        +----+
       |---+        +----+
       | G |    --> | A5 |
        ---+        +----+
+--+---+            +----+
|  | H |        --> | A6 |
+--+---+            +----+
