Sintonia

Here is a fantastic effect created by Vincenzo Di Fatta. The magician shows a red and a blue deck of cards. One of them is handed to a spectator. Now the magician and the spectator swap any card of their decks. So the magician slips one of his blue cards among the spectator's red cards, and the spectator slips one of his red cards among the magician's blue ones. Incredibly the two cards will match perfectly!