card trick without the trick Most cards can be distinguished as right-side up or upside-down, right? So just have the first card be the suit of  the card given, and encode the number 1-13 via binary using right side up / upside down as 1 / 0.  Seems much simpler to me than the way given. Daniel Kim Tuesday, February 22, 2005 um, no.  most cards cannot be distinguished by orientation.  any card upside down looks the same as it did right side up, if you're looking at the backs, and more than half the cards are the same when reversed if you're looking at the faces. so, no.  you're wrong. Pan Walker Tuesday, February 22, 2005 Some (real) card tricks actually are based on this principle. Face cards, especially, have a "thin" border end and a "wide" border end. Easier to pick them out with some practice. So in some cases this might work, but you are right, there are many cards that appear symetrical. (Diamonds in all ranks A-10, Spades, Hearts, and Clubs in even ranks 2-10) BradC Thursday, February 24, 2005   Fog Creek Home