A slot machine is a gambling game with spinning reels. Those reels have symbols on them, which land randomly after you place a bet and spin the reels. If these symbols line up, you win prizes based on which symbols fall on that “payline”.

These games have been around since the late 19th century, but they’ve done nothing but grow in popularity since then. They were originally mechanical devices that relied on springs and gears to spin the reels. Modern slot machines use a computer program called a random number generator to determine which symbols land where.

A random number generator is a computer program that cycles through thousands of numbers per second. When you hit the spin button, the program stops wherever it’s at. These numbers correspond to stops and symbols on the reels.