SimulatedBubblePacking_V1 is a geometry node chain the produces a point field and moves each point away from the nearest point until the distribution reaches equilibrium, or the simulation is stopped. The radius of each point is decided by the distance of the nearest point. This allows for a robust particle system that will spawn/pack spheres on a mesh (or in open worldspace) that never overlap, and never touch. The closer a point is to another point, the smaller the radius will be and the more aggressively they push away from each other. The result can produce very interesting and organic behaviors. 

V1_Walkthrough:

Different cool things:

Flipping the speed multiplier into negative values will cause nearest points to attract (not repel) each other, creating clusters of high energy micro structures. Similar to low density elemental atoms of 1-3 protons. dead points are collected and decayed as the micro-structures move around. It kinda looks like excited electrons jumping between shared atoms, or a kind of Game of Life.