This example visualizes a small social network as a force-directed graph, with nine named people connected by weighted links. Black circles represent nodes, and line thickness reflects link weight. Users can drag nodes, and hovering over a node displays a tooltip with the person’s name. The visualization uses d3.layout.force (from d3.v4) with gravity, distance, and charge parameters, rendering SVG circles, lines, and text. It loads node and link data from a local graph.json file and animates node positions via the force simulation’s tick event.