This is based on a wonderful trick in Bruce Elliott’s Magic as a Hobby, Cagliostro’s Spectacles. This version allows you to perform it with a single deck, and adds an additional effect which accentuates the spectator’s miraculous accomplishment. “I was given a special pair of glasses. They’re the Spectacles of Yourself. They don’t let you see things sharper, or see things darker, but you see things with amazing insight. I know you don’t believe me, but it’s true. The moment that I put them on, I realized… [the magician dons ridiculous-looking glasses] that I shouldn’t be wearing these in public. [The glasses are taken off.] That was my first insight. I thought I’d demonstrate by letting one of you have insight. In fact, you’re going to be able to do the magic. So if you ever wanted to be a magician, for 30 seconds, this is your chance.”
The glasses are put on a small table to the side. The magician takes out a deck of cards and shuffles them, cuts the deck into two halves, and puts one half on the table. A volunteer is brought onstage and asked to stand behind the table.
The magician steps to the front row and has three cards selected from their half of the deck. Those spectators hold their selected cards. The volunteer is asked to pick up the other half of the deck, mix them, and have three more cards selected, using the other side of the audience. Those three cards are also retained by the spectators who selected them.
“Let’s switch sides, so that everyone knows I couldn’t have seen the cards that were picked over there, and you couldn’t have seen these.” The three selected cards are replaced in the packets and the packets are exchanged.