A Little Light Thinking:
Good King Xerxes (he had done tshuva) had a problem. One of his key advisors had recently been hanged for high treason, and now a new spot in the king’s cabinet needed to be filled.
Since one of the prerequisites of being on the king’s staff was the ability to think logically, King Xerxes devised a puzzle that applicants needed to solve to the best of their abilities in order to be considered.
The king had two adjacent rooms wired up, so that room “A” had four switches on the wall, and room “B” had four 100-watt incandescent bulbs, each controlled by one switch (you don’t REALLY believe there were no electric bulbs before Edison, do you?). There was a 100% lightproof door installed between the two rooms. The door was kept closed.
Each applicant was allowed to set any switch to any position in the “switch room”, and take as long as he wanted to do so. Once he declared himself ready, the door to the “light” room was opened, and the switches locked in place. The applicant then had to determine which switch controlled which bulb.
Given these conditions, is it possible to determine the connection between all four switches and bulbs? How?