I'm playing with remedial graph theory and geometric sums. It's for a silly hobby, helping my friends and I write branching fiction novels together. (It's like choose-your-own-adventure but literary, not second-person.) Each chapter has x choices at the end - usually 1 or 2, sometimes more, 0 for conclusions. Threads can merge. Moderators have a desired average thread length. Chapters have an average word count. And there's a maximum story size for each.
Quite a knotty problem! Most of my authors hate math, and they all invariably love putting as many choices at the end of a chapter as the system will allow, so if you let them, you'll pretty quickly get to "heat death of the universe" estimates on when the story will be completed. So I have to code in some controls that project how big the stories will be, given what has been written so far. Then introduce some automated controls that communicate things like, "No, Moderator X, you cannot ask for three choices at the end of every chapter anymore, because you already want a desired thread length of 13 and your authors are averaging more than 1100 words per chapter. Only single-choice chapters are allowed for the time being. Merge some threads, that will help. Tell your authors to write shorter chapters."
Anyway, I'm writing those controls now. And that doesn't even get into the shape of graphs - how some can have more choices (edges) early in the story (graph), leading to shorter path (thread) lengths, and how so can have more choices later in the graph... and all of this affects the projection of how big the story will end up being, given a probable path length.
Oh and I also had to figure out how to solve for r in the geometric sum formula, which you can't do, so I got to write an approximation algorithm to find it.
Anyway, it's pretty fun. Exponential math can be addictive. It's similar math to projecting covid or the money in your retirement accounts, except more fun and less depressing. Plus, my authors are good, funny writers, and I think this will make the stories better with good plot and good conclusions, as opposed to soap operas that meander along forever. One of the stories is almost done, which means I'm also playing with markdown export, LaTeX, Pandoc, and KDP to get actual printed books.
It's all just for stupid fun, no sane hope of commercialization, just books for our own bookshelves. We've also been surveying our friends to see if we can find more authors.