街机
While hardware itself became difficult to clone, the software of games were subsequently used in unlicensed copies for other systems. Cloning of arcade video games was popular during the arcade's "golden age" in the early 1980s. Arcade games, prior to mass production, were made in limited numbers for field testing in public spaces; once news got out that a new arcade game from industry leaders like Atari was out in the open, third-party competitors would be able to scope the game and rush to make a clone of the game, either as a new arcade game or for home consoles; an occurrence which happened with "Missile Command" in 1980. This ultimately diluted the market for new arcade games.