Question: you have 3 lamps in a room .there are 3 switch on/off for the 3 lamps but they are located out side the room . how can you tell which switch goes for which lamp with entering the room only one time
Answer: turn one swish on and wait for a while . then turn it off. then turn anther one on . then enter the room
the result : the frist switch goes for the hot lamp
the second switch goes for the lighted lamp then the third switch goes for the cold unlighted lamp