The first slot machine appeared more than 100 years ago, since then this type of gambling has undergone many changes. Devices have evolved from mechanical machines to online computer games. Due to the popularity of this entertainment for money, many gamblers are trying to figure out how slot machines and slots in the casino work. Mechanical "one-armed bandits" are a thing of the past. They can still be found in some casinos in Las Vegas, but more often in the form of exhibits. Nowadays, all devices in land-based casinos have electronic filling, and the handle for launching the reels in some of them is just a tribute to tradition and imitation of the first slot machines.