Dog Plays by Sliding Ball On Treadmill While Owner Walks on it

Otis, the dog, discovered a new game while trying to grab his owner's attention as he was working out on the treadmill. He got the ball to him to play but ended up putting it on the moving belt of the machine. He seemed very fascinated to see the ball slide off it as the surface moved. He kept doing it, again and again, to enjoy himself while playing his new, accidentally discovered game.