Negative Twenty Questions

Physicist John Wheeler devised a variant of the Twenty Questions game called Negative Twenty Questions in which, unbeknownst to the guesser, everyone privately picks their own object, resulting in a game where both the guesser and the object choosers are required to narrow their choice in object with each round.

When returning Joe (let's call him) asks the standard bigger-than-a-breadbox question, if the first person says no, then the other players, who may have selected objects that are bigger, now have to look around the room for something that fits the definition. And if "Is it Hollow?" is Joe's next question, then any of the players who chose new and unfortunately solid objects now have to search around for a new appropriate object. As Murch says, "a complex vortex of decision making is set up, a logical but unpredictable chain of ifs and thens." Yet somehow this steady improvisation finally leads -- though not always, there's the tension -- to a final answer everyone can agree with, despite the odds.

Wheeler thought the game resembled how quantum mechanics worked.