I used to have a dog that was too smart to need a machine like that.
I had a dog who had a ball that sticks to walls and roll down slowly on its own. What he would do is pick up the ball with his mouth, then swing his head and let go of the ball to make it hit the window. He will then sit there and watch as the ball slowly rolls down the window. When he lands on the floor, he will pick it up with his mouth... walk back... then repeat.