The inmates at the penitentiary decided to play a little prank on one of their more, shall we say, dim witted fellow inmates. Here’s the plan, they said, "We got a hold of one of the guard's high powered flashlights. See? We'll shine in on the base of the wall tonight, when it’s all clear. You get on it and we'll lift you slowly up the wall, right on the beam of light, see? He says, "HEY, wait a minute, how dumb do you think I am?" Why? They asked. "I know what you'll do. When I get half way up the wall you'll turn off the light!"