## Two Lost Cards in a Deck

Below you can read the steps of a magic trick, as well as a video of its live performance. Your goal is to figure out how the trick is done, then perform it for your friends and challenge them to figure out the trick themselves.

- Take out from your pocket a deck of cards, which is visibly shuffled.
- Ask your first assistant to cut the deck, then take the top card from the bottom pile of cards and memorize it.
- Ask your second assistant to take the next card from the bottom pile and memorize it.
- Ask your first assistant to return his card back on the top of the bottom pile, then ask your second assistant to do the same.
- Place the two piles of cards on top of each other and cut the deck multiple times.
- Split the deck into two piles of cards, dealing consecutively one card on the left, then one card on the right, and so on, until you run out of cards.
- Take one of the two piles of cards, look at it, and guess correctly what cards were chosen by your assistants.

How does the magic trick work? Below you can see a live performance of the magic trick from Penn and Teller’s show Fool Us.

**SOLUTION**

The secret of the trick is to memorize the group of cards which are located in even positions and the group of cards which are located in odd positions in the original deck. An easy way for doing this is to split the cards into two groups, such that the cards in the first group are only spades and diamonds, and the cards in the second group are only clubs and hearts.

When the two assistants pick their cards and then return them back into the deck, the order of the cards is reversed. When you split the original deck into two piles (even after cutting it several times), each of the piles will contain a card which should not be there. For example, the group of spaes and diamonds will contain one clubs card, and the group of clubs and hearts will contain one diamonds card. These two cards are the ones which were picked by the assistants.