I finally wrote an article detailing the techniques I've been using to make organic simulations. It ranges from the classic physarum algorithm to some of my more advanced tricks.
I tried to explain things clearly, and it includes interactive parts. I hope you enjoy it!
https://bleuje.com/physarum-explanation/
Algorithms for making interesting organic simulations

Article explaining simulation algorithms that produce complex organic behaviours, starting with the classic physarum algorithm from Jeff Jones.

Thanks for the feedback about this article, I hope to see more art using these algorithms.
Here are some high resolution screenshots, just added to the article:
@bleuje Could you add some image descriptions? :) I'd love to share these, they look amazing, but I don't boost without alt text
@eikaron added alt text. I'm not inspired to give good descriptions. I thought the article in the original post is a better description for what the images contain.