Two blondes were roofing a house. One would pull out a nail and then

hammer it into the roof. Then he would pull out another nail, look

at it, then throw it over his shoulder. Blonde two eventually saw what

blonde one was doing, watched him a while and then said, "Why do you keep

throwing out every other nail?". The first blonde replied, "Because their

point is on the wrong end." The second blonde then said, "You airhead,

those nails are for the other side of the roof!"