Okay, so my kids love Rock paper scissors. I have always admired the circularity of the game in that everything gets beaten and beats the same amount of things. I also am a bit of a trekkie and was both intrigued and delighted when I came across The Lizard-Spock Expansion (cf. The Big Bang Theory).

So what has this to do with mathematics? On this link, Mathematician Alan Yuille explains the mathematics behind the game. That aside, there is also a great explanation of the rules of the expanded form and a link to when the five-item variant made its first appearance in 2008, in an episode entitled, “The Lizard-Spock Expansion.”