Roll the paper into a tube about an inch (2.5 centimeters) wide, and secure it with tape. Hold the tube up to one eye. With your palm facing you, place your free hand about an inch from the end of the tube. With both eyes open, focus on an object across the room. It appears that you’re looking at the object through a hole in the middle of your hand!

One eye sees the distant object through the tube. The other eye sees the palm of your hand. Your brain combines the two views to create the optical illusion.