You show a large dice and a ball and cover both with a tube. Then you make a magical wave with the hands, and when you lift both tubes, the ball and dice have switched places!
You repeat this until you decide to set the dice aside. But when you again raise the tube a new dice has appeared! This happens over and over until you have produced 6 large dice! The ball is completely gone!
You can view the demo at https://www.youtube.com/watch?v=22Mhvg0aRHE&feature=emb_logo