While hardware itself became difficult to clone, the software of games were subsequently used in unlicensed copies for other systems. Cloning of arcade 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. "BYTE" reported in December 1981 that at least eight clones of Atari, Inc.'s arcade game "Asteroids" existed for personal computers. The magazine stated in December 1982 that that year "few games broke new ground in either design or format ... If the public really likes an idea, it is milked for all it's worth, and numerous clones of a different color soon crowd the shelves. That is, until the public stops buying or something better comes along. Companies who believe that microcomputer games are the hula hoop of the 1980s only want to play Quick Profit". The degree of cloning was so great that in 1981, Atari warned in full-page advertisements "Piracy: This Game is Over", stating that the company "will protect its rights by vigorously enforcing copyrights and by taking appropriate action against unauthorized entities who reproduce or adapt substantial copies of ATARI games", like a home-computer clone.