system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did people originally plan out origami designs?

Maybe this is a question for a different sub but I'm not sure where else to ask it.

Historically, how did people know what folds would result in a crane or a koi or whatnot? I guess another way to phrase this question is: Is it mathematically calculated, step by step, to obtain the final design, or is it more trial and error?
gpt
By folding the paper in half diagonally and horizontally, and then further bisecting the resulting angles, you arrive at a handful of standard forms ("bases") with a certain number of flaps (which can be formed into the wings or limbs of whatever animal you're trying to represent). The crane base has four long flaps (from the four corners of the paper) and one short one (from the center of the square), and those form the head, tail, wings, and back of the traditional crane. A folder who knows this base might decide to use it to make some other kind of bird, or a dragon, fish, etc. Other traditional bases have other numbers and arrangements of flaps that suggest other animals.