Hello! I've been working on an intuitive explanation of the cosine and sine functions that could be presented to an audience of high school students with little to no knowledge of analysis. The goal was to develop a more algebraic treatment that weaved in a bit of programming and I'm quite happy with the results so far. There won't be anything particularly new for people who are already familiar with the subject but the approach I took is rather unusual so you might still find it interesting:
https://www.allthoughts.me/blog/handmade-maths-cosine-and-sine/