Light switches
Pairs of switches have to match, both up or both down, end of story. Except it's not.

At work we have a pair of light switches on the landing: one for the landing light, one for the stairwell. At the bottom of the stairs is another pair: one for the hall, the other also for the stairwell. With all three lights on, the world is a happy place as each pair of switches matches. But at going home time we have a twitch-inducing problem....

Turn landing and stairwell light off, and have a matching pair upstairs, only to leave an unmatching pair downstairs (or leave a light on overnight? No chance!).

The solution is this: to turn the landing light off, leaving the stairwell light on - this must be done by touch, so one can neither see nor feel that this pair is 'unmatched'. Then go downstairs without a glance back, turning both switches off downstairs. This way, if anyone should happen to climb over the security fencing during the night and look through the windows, they will only see matching pairs of switches.
(Frakkus is blowing bubbles in the bath, Sat 17 Dec 2011, 7:36, 1 reply)

Yes, this.
This is correct.
(Dermot O'Logical, Wed 21 Dec 2011, 14:37, closed)