Show a small plastic case. Open the lid and place three borrowed quarters into the three recessed holes. Insert a piece of paper over the quarters and close the lid. Immediately, plunge three pencils right through the holes in the case, right through the paper, right through the quarters, and right out the bottom. Show the case all around. They can actually see the pencils passing right through the case. Slide the paper out. The quarters are still there, and can be seen through the small holes. Immediately hand the case out for examination.