+----+    +------------------->+----+             
|    |    |                    |    |             
|    |----+                    | y  |             
| x  |----------okay---------->|    |------>+----+
|    |                         +----+       | z  |
|    |----+                             +-->|    |
|    |    |                             |   +----+
+----+    +-----------------------------+         
