Asking the right questions
The three-switch-one-bulb riddle is sometimes asked as a job interview question. If you're not familiar, it goes something like this: Three switches before you are wired up to a lightbulb inside of a sealed, opaque box. All of the switches and the lightbulb are off. You may toggle each switch as many times as you like, but only before you open the box, and you can only open the box once. Can you determine which switch controls the bulb? The answer is generally along the lines of: Turn on any two switches, wait a few minutes, turn off one of the two "on" switches, open the box, and touch the bulb. If the bulb is off and cold, it's controlled by the untouched switch. If the bulb is off and hot, it's controlled by the switch turned off before the box is opened. If the bulb is lit, it's controlled by the switch left on. Typically, the question ends there, and the interview moves on. Popular Mechanics even calls this solution " a satisfying answer ." H...