The cow visits the dog. The dog needs the cow. The dog needs the squirrel. The dog visits the squirrel. The lion is red. The lion is round. The lion visits the dog. The squirrel is blue. The squirrel is round. The squirrel needs the lion. The squirrel sees the cow. The squirrel visits the lion. If someone visits the cow then they are cold. If someone is round then they need the dog.
The dog does not need the squirrel.