You orient the card based on the other player's card, for their benefit. That's why I think it would be against the rules - it's the same as if you held up fing

You orient the card based on the other player's card, for their benefit. That's why I think it would be against the rules - it's the same as if you held up fingers or made a face, it's communication. Bruce and Ava decide to put the card horizontally if they see a red card, or vertically if it's black. If Bruce sees a vertical card, he knows Ava sees a red card on his head. In the game of four, the players decide one of them will guess, and two others will communicate information in binary: horizontal, horizontal: hearts horizontal, vertical: diamonds vertical, horizontal: spades vertical, vertical: clubs However this latter method only requires three players, not four. But it is similar to how professional bridge players cheat, by communicating their hand (which is hidden from their partner) with secret signals: http://www.newyorker.com/magazine/2016/03/07/the-cheating-problem-in-professional-bridge http://www.newyorker.com/magazine/2016/03/07/the-cheating-pr...