Effect
Two spectators each receive a packet of 10 cards. The magician explains that three cards will invisibly travel from one packet to the other. The three cards travel one at a time, without explanation.
When the first spectator counts their cards, only seven remain. The second spectator counts their packet and discovers 13 cards. The three cards have apparently traveled from one packet to the other.
But the experiment is not over.
The magician proposes taking things one step further: If the three cards were able to travel from one place to another, perhaps they can also return to where they started. This time, the performer places the spectator’s respective packets into two different Ziploc bags and then all three cards travel back simultaneously while the packets are sealed in those bags. Both spectators open their bags and count their cards again. Each spectator is holding exactly 10 cards.
Everything has returned to the way it was at the beginning.