Additional weaponsWith an odd number of choices, each beats half the weapons and loses to half the weapons. No even number of weapons can be made balanced, unless some pairs of weapons result in a draw; there will always be some weapons superior to others.
An example of an unbalanced four-weapon game adds "dynamite" as a trump. Dynamite, expressed as the extended index finger or thumb, always defeats rock, and is defeated by scissors. Using dynamite generally implies that dynamite burns paper, but some claim that paper would smother the fuse. The fourth option of dynamite changes each gesture's odds of winning. For instance, scissors' odds improve from 33% to 50% while rock's odds decrease from 33% to 25%. Dynamite can be used to cheat by quickly raising or lowering the thumb on the downstroke once the opponent's play is recognized. Organized rock-paper-scissors contests never use dynamite.
One popular five-weapon expansion, invented by Sam Kass and Karen Bryla, adds "Spock" and "lizard" to the standard three. "Spock" is signified with the Star Trek Vulcan salute, while "lizard" is shown by forming the hand into a sock-puppet-like mouth. Spock smashes scissors and vaporizes rock; he is poisoned by lizard and disproven by paper. Lizard poisons Spock and eats paper; it is crushed by rock and decapitated by scissors. Adding new gestures has the effect of reducing the odds of a tie, while increasing the complexity of the game.
Personally, I'm sticking with the original 3..altho I like the idea of dynamite.