+-----------+      +-----+-----+      +-----+-----+
|           |      |     |     |      |     |     |
|           |      |     |     |      |  d  |     |
|           |      |     |     |      |     |     |
|     a     |  ->  |  b  X  c  |  ->  +--Y--+  f  |  -> ...
|           |      |     |     |      |     |     |
|           |      |     |     |      |  e  |     |
|           |      |     |     |      |     |     |
+-----------+      +-----+-----+      +-----+-----+

                         +-----+
/---\                    |     |
| f |     +--------------+     +--+
\---/     |              |     |  |
          |              |     |  |
          |              |     |  |     |
          |      +-------+     +--+    -+-
          |      |       |     |        |
       +--+      +-------+     |
       |  |      |             |
       |  |      |             |
       |  |      |             |
       +--+      +-------------+          ^
          |      |                        |
          +------+                        \-\
                       testing              |
                     ascii2image          --+
 A               B
  +-------------+
  |             |
  |             |
  |      E      |        F
  |       +-----+-------+
  |       |     |       |
  |       |     |       |
  |       |     |       |
  +-------+-----+       |
 D        |      C      |
          |             |
          |             |
          +-------------+
         H               G

                AB
               /  \ 
              /    \
             /      *
            BC
           /  \ 
          /    \
         /      *
