We went to a friend's house for dinner and their house is large enough that it actually has a small elevator. The kids were, of course, fascinated and wanted to ride it. I took them into the elevator and we were trying to figure out how to turn the light on inside. There was a switch marked "On/Off" but switching it on didn't actually do anything. Stuart looked around for a second, then said "I bet you have to turn the switch on and then close the door for the light to come on." And, sure enough, that's exactly how it worked.