Editing Slot machine (section)

===Reels===
Historically, all slot machines used revolving mechanical reels to display and determine results. Although the original slot machine used five reels, simpler, and therefore more reliable, three reel machines quickly became the standard.

A problem with three reel machines is that the number of combinations is only [[cube (algebra)|cubic]] – the original slot machine with three physical reels and 10 symbols on each reel had only 10<sup>3</sup> = 1,000 possible combinations. This limited the manufacturer's ability to offer large jackpots since even the rarest event had a likelihood of 0.1%. The maximum theoretical payout, assuming 100% return to player would be 1000 times the bet, but that would leave no room for other pays, making the machine very high risk, and also quite boring.

Although the number of symbols eventually increased to about 22, allowing 10,648 combinations,<ref>{{cite web|url=http://gaming.unlv.edu/reading/Pacyniak.PDF|title=Info|website=gaming.unlv.edu|archive-url=https://web.archive.org/web/20060909064726/http://gaming.unlv.edu/reading/Pacyniak.PDF|archive-date=2006-09-09|url-status=live}}</ref> this still limited jackpot sizes as well as the number of possible outcomes.

In the 1980s, however, slot machine manufacturers incorporated electronics into their products and programmed them to weight particular symbols. Thus the odds of losing symbols appearing on the payline became disproportionate to their actual frequency on the physical reel. A symbol would only appear once on the reel displayed to the player, but could, in fact, occupy several stops on the multiple reel.

In 1984, Inge Telnaes received a patent for a device titled, "Electronic Gaming Device Utilizing a Random Number Generator for Selecting the Reel Stop Positions" (US Patent 4448419),<ref>{{US patent|4448419|Electronic gaming device utilizing a random number generator for selecting the reel stop positions}}</ref> which states: "It is important to make a machine that is perceived to present greater chances of payoff than it actually has within the legal limitations that games of chance must operate."<ref>
{{cite journal|last=Collier|first=Roger|date=1 July 2008|title=Do slot machines play mind games with gamblers?|journal=Canadian Medical Association Journal|volume=179|issue=1|pages=23–4|doi=10.1503/cmaj.080870|pmc=2464464|pmid=18591518}}</ref> The patent was later bought by [[International Game Technology (1975–2015)|International Game Technology]] and has since expired.

A virtual reel that has 256 virtual stops per reel would allow up to 256<sup>3</sup> = 16,777,216 final positions. The manufacturer could choose to offer a $1 million jackpot on a $1 bet, confident that it will only happen, over the long term, once every 16.8 million plays.