+-------------+                         +------------+
  | Composition |<>---------------------->| Compositor |
  +-------------+                         +------------+
  | Traverse()  |                         | Compose()  |
  | Repair()    |                         +------------+
  +------^------+                                |
         |                       +---------------+-----+
         |                       |                     |
_________|________________   +------------------+  +---------------+
|  compositor->Compose() \|  | SimpleCompositor |  | TeXCompositor |
+-------------------------+  +------------------+  +---------------+
                             | Compose()        |  | Compose()     |
                             +------------------+  +---------------+