Ah, yes, the in/out/in/out thing is a big motivator. My dad had a big grey tabby that would sit at the front door and give out a meow that sounded for all the world like "I want out". When he wanted in, he'd grab the screen door in his claws and 'knock'. He's the same cat who got first dibs on the turkey while it was cooling one Thanksgiving. From the damage, he preferred white meat. It took us kids quite a while to convince Dad that cat spit didn't ruin the whole bird. LOL