This is a nice little effect from John Kennedy. You show a little paddle, which has four different shapes on it. Each shape is a different colour; the paddle is shown to be the same on both sides. Your spectator selects a shape and you select a colour. Now with a shake, your spectator's shape changes into your colour. Once again the paddle is shown both front and back. Your spectator now selects a colour and you select a shape and once again with a shake the shape changes in to the selected colour (this looks really weird) now you give the paddle one more shake and all the colours on one side of the paddle change position. You may hand this out for examination and they will find nothing!