===============================================================================
Steps [0] through [4]
===============================================================================

class Problem7
+-------------------------------------------------------------------+
|      +---+      +---+      +---+      +---+      +---+      +---+ |
| args | *-+-+ F1 | * |   F2 | * |   B1 | * |   B2 | * |   B3 |   | |
|      +---+ |    +-+-+      +-+-+      +-+-+      +-+-+      +---+ |
+------------+------+----------+----------+----------+--------------+
             |      |          |          |          | 
      <------+      | [1]      | [2]  [3] +--+   [4] +------+
class Frippy        |          |             |              |
+-------------------+----------+-------------+--------------+--------------+
|                   V          |             |              |              |
| +----------+   +----------+  >+----------+ | +----------+ | +----------+ |
| |   +----+ |   |   +----+ |   |   +----+ | | |   +----+ | | |   +----+ | |
| | x |    | |   | x |0   | |   | x |0   | | | | x |    | | | | x |    | | |
| |   +----+ |   |   +----+ |   |   +----+ | | |   +----+ | | |   +----+ | |
| |          |   |          |   |          | | |          | | |          | |
| |   +----+ |   |   +----+ |   |   +----+ | | |   +----+ | | |   +----+ | |
| | F |    | |   | F |null| |   | F |null| | | | F |    | | | | F |    | | |
| |   +----+ |   |   +----+ |   |   +----+ | | |   +----+ | | |   +----+ | |
| +----------+   +----------+   +----------+ | +----------+ | +----------+ |
|                                            |              |              |
+--------------------------------------------+--------------+--------------+
                                             |              |
class Boingo                                 |              |
+--------------------------------------------+--------------+--------------+
|                                            |              |              |
| +----------+   +----------+   +----------+ +>+----------+ +>+----------+ |
| |   +----+ |   |   +----+ |   |   +----+ |   |   +----+ |   |   +----+ | |
| | a |    | |   | a |    | |   | a |    | |   | a |null| |   | a |null| | |
| |   +----+ |   |   +----+ |   |   +----+ |   |   +----+ |   |   +----+ | |
| |          |   |          |   |          |   |          |   |          | |
| |   +----+ |   |   +----+ |   |   +----+ |   |   +----+ |   |   +----+ | |
| | b |    | |   | b |    | |   | b |    | |   | b |null| |   | b |null| | |
| |   +----+ |   |   +----+ |   |   +----+ |   |   +----+ |   |   +----+ | |
| +----------+   +----------+   +----------+   +----------+   +----------+ |
|                                                                          |
+--------------------------------------------------------------------------+

class String
+----------------------+
|                      |
| "grok"               |
|                      |
+----------------------+