This example shows a small social network of six people organized into three groups, with connections of varying strength indicated by thicker or thinner links. The visualization is rendered as an SVG using the D3.js version 4 library, employing the older `d3.layout.force` API to simulate node positions and `force.drag` for interaction. Node labels are drawn from the `name` field in the data.json file, while the `weight` property of each link drives the stroke-width of the connecting lines, using `Math.sqrt` to scale the visual thickness.