WMS entered the reel-spinning slot machine market in 1994, and its products have helped to move the industry trend away from generic mechanical slot machines and toward games that incorporate familiar intellectual properties. For more than a century beginning in the late 1800s, mechanical slot machine reels employed limited themes: card suits, horseshoes, bells and stars, varieties of fruit, black bars and the Liberty Bell. WMS's video gaming roots would prove to be its strength when, in 1996, it introduced its first hit casino slot machine, "Reel ‘em In", a "multi-line, multi-coin secondary bonus" video slot machine. WMS followed this with a number of similar successful games like "Jackpot Party", "Boom" and "Filthy Rich". Meanwhile, by 1996, WMS had transferred all of the copyrights and trademarks in its video game library to Midway, including "Defender", "Stargate", "", "Joust" and "Smash TV", as it took Midway public and finally spun it off in 1998. With the closing of its pinball division in 1999, WMS focused entirely on the gaming machine industry. During the 1990s, that industry grew as additional states permitted casino gambling and video lottery games and as Native American tribes built gaming casinos.