Slot variance is a measure of risk associated with playing a slot machine. Full pay Jacks or Better is also known as 9/6 Jacks or Better since the payoff for a full house is 9 times the bet, and thepayoff for a flush is 6 times the bet. Pay tables allocate the payouts for hands and are based on how rare they are, the game variation, and the decision of the game operator. Even when the use of these gambling devices was banned in his home state after a few years, Fey still couldn't keep up with demand for the game elsewhere. A slot machine does not afford such an opportunity. Wild Symbol Wild symbols act like joker cards in a slot game. The resultant list was widely publicized for marketing purposes (especially by the Palms casino which had the top ranking). Some of the most popular are the video poker machines, in which players hope to obtain a set of symbols corresponding to a winning poker hand. Slot machines include a currency detector that validates the money inserted to play. 30 Modern slot machines are controlled by eprom computer chips and, in large casinos, coin acceptors have become obsolete in favor of bill acceptors. But the player still needs to get at least two of them in modern slot games. The machine is then activated by means of a lever or button, or on newer machines, by pressing a touchscreen on its face. "Skill stop" buttons were added to some slot machines by Zacharias Anthony in the early 1970s.