In game theory, there’s a thing called the Prisoner’s Dilemma, which you may have heard of. It happens that there is also a British game show (called, hilariously, “Golden Balls”) that uses PD as its final round: There’s a pot of money at stake, and the final two contestants must make a choice to either split the pot or try to steal it — and they must disclose their choices simultaneously.

• If both say “split,” the pot is split evenly.

• If one says “split,” but the other says “steal,” the stealer gets the whole pot.

• If both say “steal,” nobody gets anything.

Security maven Bruce Schneier is of course aware of PD, and even mentions it in his book Liars & Outliers. He’s come across this game show, too, and in so doing found this very interesting final round. Watch it.