Anybody who has coded Game of Life can draw a parallel to this. Simple rules can lead to arbitrarily complex systems. I'm all on board with this concept. Graph theory is amazing and useful in many ways we don't understand yet. I'm all on board with this concept as well.

But a graph has nodes and edges. Nodes, in this case, can be particles.. I guess? But what are the edges? When a "simple rule" is applied to a collection of particles, what is the force that connects them after the interaction? I read some of the material in detail and skimmed some of the rest, but there was a lot of setup and cool graph visualizations and not a lot speaking to this core question.

Disclaimer: I'm not a theoretical physicist but I have read "Quantum Physics for Babies" at least 50 times.