A brief history of Slot Machines from Wikipedia

A slot machine (American English), known variously as a fruit machine (British English), puggy (Scottish English),^[1] the slots (Canadian English and American English), poker machine/pokies (Australian English and New Zealand English), fruities (British English) or slots (American English), is a gambling machine that creates a game of chance for its customers. Slot machines are also known pejoratively as one-armed bandits because of the large mechanical levers affixed to the sides of early mechanical machines and the games' ability to empty players' pockets and wallets as thieves would.^[2]

A slot machine's standard layout features a screen displaying three or more reels that "spin" when the game is activated. Some modern slot machines still include a lever as a skeuomorphic design trait to trigger play. However, the mechanics of early machines have been superseded by random number generators, and most are now operated using buttons and touchscreens.

Slot machines include one or more currency detectors that validate the form of payment, whether coin, cash, voucher, or token. The machine pays out according to the pattern of symbols displayed when the reels stop "spinning". Slot machines are the most popular gambling method in casinos and constitute about 70% of the average U.S. casino's income.^[3]

Digital technology has resulted in variations on the original slot machine concept. As the player is essentially playing a video game, manufacturers are able to offer more interactive elements, such as advanced bonus rounds and more varied video graphics.