That's what I did when I recently came across the same model. Here's my CPU-based implementation (in Rust): https://github.com/mindv0rtex/physarum

You can get some fun patterns even at much smaller scale, so a CPU-based approach should be entertaining enough. That said, I had no knowledge of shaders either before this project! I'm johnowhitaker on twitter or email - happy to chat if you want to talk specifics.