Fans of The Big Bang Theory will already know about this variant on the traditional game, Rock-Paper-Scissors. Adding two new moves–“Lizard” and “Spock”–increases the number of possible combinations in a two-player game from three to 10 (assuming we do not care about who is the first or second player), which greatly decreases the chance of a tie. This is exactly the reasoning that Sheldon gives for using the extended version:
But do you know the real story behind the game? Karen Heyman shares the account of how engineer Sam Kass invented the game with his now-wife Karen Byrla when they were students at Carnegie-Mellon University.
For a pair of geeks, Spock’s Vulcan Salute was an obvious choice for an additional gesture. But what else could they use? At first they considered another geek favorite, a sock puppet, since it’s easy to mime. They quickly discarded it, because really, a sock against Spock? “We came up with a poisonous lizard,” says Kass, “Lizard Poisons Spock was the first of the new rules, and everything else kind of fell out from there.”
The expanded RPS turned out to serve a secondary role as a “Geek Test,” according to Kass. As he described the rules, he discovered the world is divided into our kind, and those who need to have “Paper Disproves Spock” explained to them.
Why five gestures? To quote Spock himself: “It’s logical.”
“So long as you have an odd number of hand signals, you can create a fully balanced graph where everything is beaten and beats the same number of things,” says Kass, “Four doesn’t work, because one will be unbalanced; but five works.”
It is a bit easier to understand the game from the following graphic:
Big Bang revisited the game again in the clip below, giving Kass credit for developing the game:
Now, there is a robot that beats humans at Rock-Paper-Scissors every time using high-speed vision. According to the Automaton blog, it’s too fast for players to tell that the robot is cheating. No word on whether the robot will be programmed to include Kass’s extended moves, but at least Sheldon’s dream of the singularity is one tiny step closer.