The art of counting cards is one that requires you to memorize the deck of cards once it has been put through a shuffle. The player is able to gain an advantage over the dealer due to being in a position to recall the cards and know the order in which they'll appear. Another method that is popular is eye-tracking software, which can be used with slot machines and video poker games and blackjack. The software will observe eye movements and recognize the moment when a user clicks the spin button. When that happens, it will allow the player to make a profit, protect themselves from loss, or take bets.
