This example displays a small social network as a force-directed graph, with nodes representing named individuals and lines (links) sized by a numeric weight. It uses the older `d3.layout.force` API from D3 v4 (and also loads D3 v2) to simulate physical motion, making nodes draggable and repositioning linked elements on each tick. Data comes from a local JSON file, and the rendering is done with SVG circles, text labels, and lime-colored line elements, all styled via inline CSS.