How to Open Doors: Prompt

I have had 16 cats throughout my life. Their back stories have been as different as their personalities. They were/are, of course, all beautiful and intelligent, but only a few have figured out how to open doors. Three, to be exact. Our cats are all indoor cats and the ones who are able to open doors only do so on inside doors (although Banshee could open the front door, he only ever showed off when one of his humans was there to be impressed).

For this prompt, I would like you to think about a...