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