Animal
  | 
  ->  Mammal
        |              |             |
        |              |             |
        |              |             --> furColor()
		|              |
		->   Lion      -> Wolf
               |            |
			   |            |
			   --> roar()   --> howl()
			   
			   
Mammal m = new Mammal()
m.furColor()			

Animal a = m;

Lion l = new Lion();
l.furColor();
l.roar();
m = l;

Wolf w = new Wolf();
m = w;
Animal animal = new Animal();
w = (Wolf) animal;
w.furColor();
w.howl(); <-- Error