take a £20 note place it over the rim of a pint glass then place a stack of four 2p coins on top the note (so there balancing on the rim of the glass) now hold the loose end of the note with your hand (very steady) now the note should have a larger area . Dont move the hand holding the note . Use your pointing fingerfrom the other hand and hit the middle of the note . If you do it right the note will move but the coins that were on top of it will still be stable on the rim of the glass . JUST REMEBER TO NEVER MOVE THE HAND THATS HOLDING THE NOTE OR ELSE THE COINS WILL FALL .