[The game] involves, say, four people: Michael, Anthony, Walter, and Aggie. . . . When Michael leaves the room, the three remaining players don’t communicate with one another at all. Instead, each of them silently decides on an object [in the room]. Then they call Michael back in. . . .
Michael asks Walter: Is the object bigger than a breadbox? Walter–who has picked the alarm clock–says, No. Now Anthony has chosen the sofa, which is bigger than a breadbox. And since Michael is going to ask him the next question, Anthony must quickly look around the room and come up with something else–a coffee cup!–which is smaller than a breadbox. So when Michael asks Anthony, If I emptied out my pockets could I put their contents in this object? Anthony says, Yes.
Now Aggie’s choice may have been the small pumpkin carved for Halloween, which could also contain Michael’s keys and coins, so when Michael says, Is it edible? Aggie says, Yes. That’s a problem for Walter and Anthony, who have chosen inedible objects: they now have to change their selection to something edible, hollow, and smaller than a breadbox.
So a complex vortex of decision making is set up, a logical but unpredictable chain of ifs and thens. To end successfully, the game must produce, in fewer than 20 questions, an object that satisfies all of the logical requirements: smaller than a breadbox, edible, hollow, etc.