This is an ISF shader for simulating the slime mold Physarum polycephalum. The simulation is based on “Characteristics of pattern formation and evolution in approximations of physarum transport networks” by Jeff Jones (PDF available here), and this webpage by Sage Johnson is another excellent resource. This particular shader is converted from these ShaderToy shaders by @MichaelMoroz:
This is a multi-pass shader that is intended to be used with floating-point buffers. Not all ISF hosts support floating-point buffers. Videosync supports floating-point buffers in v2.0.12 and later, but https://editor.isf.video does not appear to support floating-point buffers. This shader will produce very different output if floating-point buffers are not used.