Hi, I'm the author of the post. I don't normally release my code, but in this case I did post a gist of the main function to Twitter: https://gist.github.com/thobbs/e879b7dad8f3733d58d1

I'm using Quil, which is a Clojure wrapper for Processing. The source is quite dense, so it's hard to understand without following the post. It's mostly about tweaking probability distributions along gradients.