This example visualizes a small social network of seven people, showing connections as green lines whose thickness reflects link weight, with labeled purple nodes positioned by a force-directed layout. The graph uses a fixed JSON dataset with node names and group assignments, rendered as SVG. It leverages the D3 v4 `d3.layout.force` API to simulate physics, enabling nodes to be dragged and repositioned interactively. Link widths are set via `Math.sqrt(d.weight)`, and both circles and text labels are styled through CSS.