Multi-line slot machines have become more popular since the 1990s. Liberty Bell was a huge success and spawned a thriving mechanical gaming device industry. It contained five drums holding a total of 50 card faces and was based on poker. After some "cheat-proofing" modifications, the video slot machine was approved by the Nevada State Gaming Commission and eventually found popularity in the Las Vegas Strip and downtown casinos. Cerracchio, R.
However, this distinction is not universally observed in the English-speaking world. The first true video slot machine was developed in 1976 in an industrial suite in Kearny Mesa, CA by N. Some of the most popular are the video poker machines, in which players hope to obtain a set of symbols corresponding to a winning poker hand. The two Iowa cases of State v. The machine pays off based on patterns of symbols visible on the front of the machine when it stops.