The dog chases the squirrel. The dog does not eat the squirrel. The dog is nice. The squirrel chases the dog. The squirrel is nice. The squirrel is rough. The squirrel needs the dog. If something needs the dog then the dog needs the squirrel. If the squirrel chases the dog and the dog does not need the squirrel then the dog chases the squirrel.
The squirrel chases the dog.