Why am I writing about origami here? Partly because I'm excited. I bought some methyl cellulose for the first time, and it's like some kind of wonder potion. You dissolve it in water and smear it all over some paper and when it dries, the paper has gained magical origami powers. Suddenly it's stronger, it's crisper, and it holds a fold better. What a wonderful chemical. It cost $25 for a tiny bag of the stuff, but that bag will probably last me a decade, so it's all good.
The other reason I want to write about origami at the moment is because I feel it's my duty to spread the joys of origami to fellow geek-kind.
Origami is a geek hobby if ever there was one. There's more science behind it than most people realize. Designing a model has close ties to circle packing. There's math involved (PDF) that I just barely understand.
It's is deeply satisfying in exactly the same way computer programming is satisfying. It's the satisfaction of taking a set of very simple rules and ideas, manipulating them in novel ways and coming up with something cool.
Origami actually has a lot of similarities to programming. There are primitives: mountain fold, valley fold. They are combined into something like procedures: reverse folds, sink folds, pleats and crimps. And those procedures are combined into more complex maneuvers, and when you combine them enough you get a finished model.
There are "bases" that are essentially design patterns: certain combinations of folds that are used over and over in different models. All of these things can be put together in novel ways (recursively!). A book of origami diagrams is essentially a book of algorithms.
At the same time there are constraints: use a square, don't cut the paper, etc. The size of the paper is a constraint. The kind of paper you use is a constraint: some kinds of paper fold better than others. In the same way people get a kick out of making impressive videos in a few kilobytes of RAM, there's a great satisfaction in making a model with a dozen flaps out of something that started with four corners. The constraints define a universe of rules that's small enough to understand and master, yet large enough to leave a lot of possibilities. The same square can be folded into a spider or an elephant or a race car or a man on a horse.
But origami is different from programming because (obviously) it's 3D. There's a lot of thinking involved, but there's also a bit of manual dexterity. It's a good feeling to shape matter with your hands. And when you're done you end up with something tangible in a way that a program isn't. You can stick it on the shelf or give it away as a present.
Most people don't understand how complex origami can get. Check out the websites of Brian Chan, KAMIYA Satoshi, Robert Lang, and Gilad Aharoni. It's all (usually) from a single uncut square. It still amazes me what people can create.