This is a Reasonable Facsimile Of A Cat — it’s in the rules, really, check it out (rule #3.)

I could go for a high-tech cat door, with a little keyboard interface for the cats to punch in a combination for access, less a PIN-code than some numerical task they couldn’t perform under certain conditions, like they have live prey in their mouths that will escape inside the house, or they are weasels (etc) and not really our cats.

I’ve heard that other cats (and even other animals) sometimes learn to use your cat door once they realize there’s a bowl of food inside, but that you can get fancy (i.e., expensive) electronic doors that ID your cat on the way through.

People near us have built a skinny wooden ramp up from the ground to their kitchen window. The cat walks up and knocks on the window to get in. In good weather, they can just leave the window open for the cat (though maybe all of his friends, too, now that I think of it). You could build an elaborate series of ramps and ladders up to your bedroom window and be the envy of the town. Until the rabid badgers figure it out.

Stupid cats.