That looks so fun. It reminded me of a cat door. The cat would go out the door and a machine would close the door behind it. I bet thing would like it also, from the Addams family. If you sit there and think of some other ideas, it turns out not to be worthless, but can be used for other applications. Like, if you are in a bathroom and someone walks in on you, it would shut the door for you without you having to shut the door in a person's face.