+---------------+
                +-------|     class     |-----------------------------+
                |       |===============|                             |
                |       |   Animale     |                             |
                |       +---------------+                             |
                ^                                                     ^
                |                                                     |extends
      extends   |                                                     |
                |                   +---------------+                 |
                |                   |  interface    |                 |
      +-------------------+         |===============|                 |
      |      class        |         | AcquaticoI    | implements +-----------+       
      |===================|         |               |<---------- | class     |
      |   Mammifero       |         +---------------+            |===========|
      +-------------------+                  ^                   | Acquatico |
                ^                            |                   +-----------+
                |                            |
                |                            |
      extends   |                            | implements
                |                            |
                |       +---------------+    |
                +-------|     class     |----+ 
                        |===============|
                        |    Cetaceo    |
                        +---------------+