Description
Show two large metal nails and hand one of them out to a spectator asking him to try and repeat what you are about to do. Hold the nail between your fingers, concentrate and slowly start to bend it until you make with it a 90° angle. Then hand it out to the spectator for examination. The spectator naturally will neither be able to bend his nail or bend back yours!
The metal nails are cm 10,2 (4) long.