Changing Run Velocity to a negative value results in the cat chasing the dog. Changing the Chase velocity to a negative value results in the dog running away from the cat. A delay was added to simulate the dog tracking the cats past position using information the cat left behind (like cat scent) or tracks. A cat delay was added to allow the cat to run from the dogs past position. Threw in a time delay dictated light speed signaling limit for fun plus additional delay factors for the dog and cat reaction speeds on top of the light speed limit.