Dad made the same joke about the door whenever someone new came over: it had three speeds, midget, normal, and basketball player. So you could see who was there!
No one got it. He'd say "the windows!" and then the new person would look back and see the windows in the door, but by then they'd forgotten Dad's joke because they really hadn't been paying attention to what he said. It wsas all just hellos and greetings and no one listens closely to those.