Nathan has three light bulbs hanging from the ceiling of his living room. After searching everywhere for the switches, he finds them – much to his annoyance – in the cellar. He wants to find out which switch corresponds to which light bulb… but he is a lazy guy, he'd rather avoid walking up and down the stairs a couple of times just to figure this out. How can he solve his problem in the laziest way possible (without outside help)?
[Hint]
