wow, this is really well done! i love the user interface for changing parameters (friction, gravity,etc.) and just overall smoothness seems as if the algorithm

wow, this is really well done! i love the user interface for changing parameters (friction, gravity,etc.) and just overall smoothness seems as if the algorithm grows unstable for very high node repulsion. even with a few nodes you can tell it is getting caught in a local energy minimum, plus the oscillations are jarring. maybe just cap the repulsion strength at 50k? have you thought about adding hover text, upon a mouseover of the vertices? also, maybe instead of spring tension, one could use fixed lengths given by the weights of another text file. giving user generated meaning to the edge lengths.