Efron's Dice

thingiverse

This is the set of non-transitive dice created by Bradley Efron. Red die: 4,4,4,4,0,0 Yellow die: 3,3,3,3,3,3 Green die: 6,6,2,2,2,2 Blue die: 5,5,5,1,1,1. Two players pick a die each, roll them, and the player who gets the highest number is the winner. What's special about these dice is that none of them is the best. For each die there's another one that beats it with a probability of two-thirds. In this case red beats yellow, yellow beats green, green beats blue, and blue beats red. So, contrary to intuition, the player who has the advantage is the one who chooses die second. Useful for showing this unexpected property in a game. More info at https://en.wikipedia.org/wiki/Nontransitive_dice.