Four squares of material change to one larger circle of material in a change bag. When the change bag, which is square, is turned inside out, it too changes to a circle. The square bag is shown empty by turning it inside out. It is then turned right side out, and one by one, four squares of material are placed into the empty pocket. Attention is drawn to the fact that the bag is square, and that you have placed four squares inside it. The bag is now turned inside out again, however this time inside is one round or circle of cloth. The audience is told that the four cloths, which were once square, have now become one round cloth. The bag is turned inside out a second time and actually has turned "round". This is a delightful baffling effect. Wonderful for pre-school shows where the children are learning shapes.