This is something that I heard recently from a Local Inspector that demonstrates good deductive reasoning, I don't know if he thought of it but I guess he could have, He's pretty sharp.

(purely hypothetical - not to code obviously)

If you have a Light in the Attic and 3 switches in the Basement (1 turns on that light) - How can you fgure out, by yourself, which switch it is and only make the trip up to the Attic 1 time?

The Attic is not within sight, no one else there [Linked Image]

Bill