Original author here. I've been reading this website for years. Imagine my shock when I saw my own article on the front page! I'm glad people are enjoying it.

Quick fact about the way the interactivity is done, all of the code for it is in this blogpost.js file: https://aaaa.sh/creatures/blogpost.js, which is only about 100 lines long. Each block has a list of scripts that it pulls from like so:

<div class="code-example" scripts="grid-sm 2d-vector-gfx-lib draw-grid full-algo-intro feather-canvas-edges"></div>

and then there's a set of script tags with those ids. I figured it was a nice solution!