When playing slot, you can earn credits based on the symbols that line up on the pay lines. These pay lines can be simple and straight or they can take a zig-zag shape across the reels. Some slots allow players to choose how many of the pay lines they want to bet on, while others have fixed paylines and you can’t change them. You can also find games with stacked symbols which increase your chances of hitting the winning combination.

The history of slot begins in the 19th century when two New Yorkers named Sittman and Pitt created a machine that allowed players to win by lining up poker hands. Their invention was popular but a mechanic by the name of Charles Fey improved on it in 1887 by adding a third reel and changing the symbols to diamonds, spades, horseshoes, hearts and liberty bells. Three aligned liberty bells constituted a winning hand.

Modern slot machines use microprocessors to determine the probability of each symbol appearing on each reel. The computer assigns a different probability to each symbol, which is then displayed on the machine’s screen. This allows the manufacturer to compensate for the fact that different combinations of symbols will be more likely to appear on certain reels than others. It also enables them to compensate for the fact that some of the symbols may not appear on the reels at all, since it takes the same amount of time for each symbol to reach the sensor.