My daughter got a kitten, Jewel, about a year ago. She's now a teenage rambunctious maniac running around the house constantly knocking everything off the counter - the cat, that is, not my daughter. Well, I guess that too, but that's a different story.
Anyhow, what I noticed was Jewel was rubbing her cheeks on everything. She'd rub up against vases, glassware, picture frames, pencil cups, lamps. Get the hint here? Suffice it to say, we have a lot of repaired stuff in the house.
In the past with our other cats, we would just go out and buy one of those corner cat combs. They're cheap and very effective. But as I was trying to tell my daughter, who at the time was heads down distracted with musical.lys from her friends, that we needed to go out and buy one these, after which she just kept saying "what? what?", I blurted out "a cat comb!" And if you say that fast enough with enough fervor in your voice, it sounds just like "catacomb".
Of course, the first place I went to was Instructables to look for a cat-a-comb, not a cat comb, but a cat-a-comb. Nothing. I searched the web. Nothing. That's how this project came to be. If it doesn't exist, build it. One of the side benefits of this project was that I learned a bit more about catacombs and was able to share that with my kids, who thought this was just too weird and too creepy.
At first I had very high ambition. The Cat-a-Comb was going to be a tunnel-like cavern where Jewel would explore, hang out, etc., and she would rub her cheeks on the skulls and bones. After a few initial test prints of very large designs it became apparent that it would take months to print not to mention I was completing only about 10% of the print jobs. After many iterations, the final design just ended up being a simple archway with the comb teeth inside the arch for cheek rubbing and the skull and bones on the outside for decoration.
One important piece of advice upfront: buy a lot of filament. Buy 2x more than you think you need. I ran out twice and it looks too patchwork'y.