In the wild, cats have to hunt if they want to eat — which means running, jumping, climbing. Indoor cat food, on the other hand, is often lazily lying in a full bowl, and the only physical exercise required from the cat is to duck his head. This lead to many issues, including excess weight and boredom — I'm not going to give a lesson about cat feeding, I advise you to google for this topic.
There is, however, a simple solution : puzzle feeders, or food puzzles. A puzzle feeder is a device with which the cat has to actually interact in order to get his food. It can either be physically stimulating (e.g. a simple ball with a hole for food to get out) or mentally stimulating, or both. In any case it should help the cat eating more slowly and stop when he's not really hungry anymore (which, in principle, happens sooner when you eat more slowly).
There are a number of commercial solutions, some of which are cheap yet quite interesting. But of course if you're reading instructables you must be more interested in DIY solutions. I started with simple devices such as a plastic bottle with a hole (works, but expect grease and crumbs of dry food everywhere in the room) or a small pot too thin for the cat head (works well, as long as it's fixed), but somehow wanted something a bit more stimulating.
Here comes the wooden cat puzzle feeder tower.
Disclaimer : This is my first wood work (and my first instructable), so don't expect professionnal tips… This project was mainly a pretext to get my hands on woodworking. In addition, English is not my first language, so expect grammatical issues and (in particular technical) vocabulary flaws.
First, draw your device on a piece of paper (or a computer, or whatever). It will help you avoid obvious flaws, improve efficiency, get dimensions, etc. Below are plans for mine — sorry for the poor picture, I may redraw it later if needed.
How it works, from top to bottom :
It's a good idea to make a cardboard prototype and give it to your cat, it really helps improving things