Hey glad you liked it. No low level data struct - my implementation in godot was pretty rough and ready. I used a tile map for the fungus "growth" layer and have an algorithm that tries to grow each network by X pixels per frame (picks a random tile in the network and tries to grow from it either in a polar or branching direction). I then also have an "attack" tile map layer that scans the growth layer tiles directly adjacent to the "road" tiles each frame and checks if a spore bomb tile pattern or plume tile can be created (depending on the contents of the adjacent cell). A lot of room for improvement - a custom low level implementation would more than likely be more performant - but I found the built in tile map helper functions were perfect for this rapid prototype.