This example visualizes a small social network of six people using a force-directed graph. It shows nodes representing individuals and links representing connections with varying thickness, where thicker links indicate stronger relationships. The graph renders as an SVG canvas and supports interactive dragging of nodes. The code uses the D3.js v4 library, specifically the `d3.layout.force` API for physics simulation, along with `force.drag` for node interaction, and loads the network data from a JSON file containing node names, group assignments, and edge weights.