We used to have a Gordon Setter named Celtie, (pronounced like"keltie"), who loved to chase a tennis ball. Even when she came in the house, that's what she wanted to do. When no one would play with her, she would go to the top of the second floor steps, ball in mouth, and then drop the ball down the steps. By the time the ball rolled down 1 or 2 steps she would come flying down the steps and chase the ball. She learned to entertain herself which is a sign of intelligence. But then, anyone who has a Gordon Setter would not be too surprised.