The cat eats the mouse. The dog eats the cat. The mouse needs the dog. If something is round and it eats the mouse then it chases the dog. If something is kind then it needs the cat. If something eats the dog and it is round then it chases the dog. If something needs the mouse and it chases the mouse then it is round. If something needs the dog then the dog chases the mouse. If the cat eats the mouse and the cat is kind then the mouse eats the dog.
The dog needs the dog.