This example shows a social network graph of friends, with nodes representing people and directed links showing relationships. The graph is rendered as SVG, and users can drag and hover over nodes to interact with the visualization. The code uses `d3.forceSimulation` with `d3.forceLink`, `d3.forceManyBody`, `d3.forceCollide`, and `d3.forceCenter` to position the nodes, while data is loaded from a local `graph.json` file.