  The 21 card trick is well known. It was recently shown in an episode of the
popular YouTube channel Numberphile. In that trick, the audience is asked to
remember a card, and through a series of steps, the magician is able to find
the card. In this article, we look into the mathematics behind the trick, and
look at a complete generalization of the trick. We show that this trick can be
performed with any number of cards.
