After spending several hours pouring over the puzzles in the Labyrinth, you work up quite a thirst. So you stroll down the hall to the company soda machine. The machine has three buttons, which dispense "Royal Fizz-Cola", "Dyspepsia", and a third which randomly distributes either one. Years of experience have shown that the labels are never correct. So the "Royal Fizz-Cola" button might always yield Dyspepsia, or it might randomly deliver either, but never reliably "Royal Fizz-Cola".