Rock-paper-scissors-lizard-Spock is an expansion of the classic selection method game rock-paper-scissors. It operates on the same basic principle, but includes two additional weapons: the lizard (formed by the hand as a sock-puppet-like mouth) and Spock (formed by the Star Trek Vulcan salute). This reduces the chances of a round ending in a tie (from 1/3 to 1/5). The game was invented by Sam Kass with Karen Bryla, as "Rock Paper Scissors Spock Lizard".
The game was mentioned in four episodes of The Big Bang Theory. According to an interview with Kass, the series producers did not ask for permission to use the game, but he was later referenced in an episode in the fifth season for which he thanked them on his website.
The rules of Rock-paper-scissors-lizard-Spock are:
- Scissors cut paper
- Paper covers rock
- Rock crushes lizard
- Lizard poisons Spock
- Spock smashes scissors
- Scissors decapitate lizard
- Lizard eats paper
- Paper disproves Spock
- Spock vaporizes rock
- Rock crushes scissors
There are ten possible pairings of the five gestures (fifteen if you count ties); each gesture beats two of the other gestures and is beaten by the remaining two. As with the original rock-paper-scissors game, if two players pick the same gesture, it is a tie. The original rules (rock beats scissors, scissors beats paper, paper beats rock) remain the same.
- "... and paper scissors". The Times. June 11, 2005. Archived from the original on May 31, 2010. Retrieved 2010-11-04.
- "Rock Paper Scissors Spock Lizard". Sam Kass. Retrieved 2010-11-04.
- "The True Story behind RPS, Lizard, Spock". Archived from the original on May 19, 2012. Retrieved January 10, 2014.
- "Rock Paper Scissors Spock Lizard". Sam Kass. Retrieved 2014-01-21.