I've never seen them getting up, just catch them already on top. I have an idea the conversation goes something like this.They are all so gorgeous!
GoldyCat - How only do your kitties get on the doors like that?
Shareena: Let's go get Goldy. She knows how to open closet doors.
Iris: Okay, the doors are open now. (Thanks, Goldy). So what's next?
Shareena: Meowmy's put these nice shelves in here for us to climb. Let me show you.
Iris: Okay, got it! Huh? Whadda ya mean I can't get back down the same way I came up? Let me think about this. Aha! I figured it out.