Here’s what happens:

The spectator provides the materials, simple enough that they can be found around the house. Using four index cards (or business cards, or scraps of paper), four designs are drawn. The cards are mixed, then cut or torn in half; there are now eight pieces. A variety of fair actions are followed, with everything away from the performer’s view. The choices are legitimate; two of them involve freely tossing coins. And yet, all of the half-cards end up correctly paired. It’s a baffling series of incredible results.