Force-Directed Graph simulation using Fruchterman-Reingold spring layout.
Explore Erdős-Rényi random graphs, Barabási-Albert scale-free networks,
and Watts-Strogatz small-world graphs. Nodes are coloured by degree
centrality — blue for low-degree nodes, orange for high-degree hubs. Drag
nodes to interact. The live degree distribution histogram shows the
characteristic power-law tail of scale-free networks.