This example visualizes a family network as a force-directed graph, with eight named nodes connected by weighted links that represent relationships. The code uses D3 v4’s `d3.layout.force` to compute node positions and render the structure as an SVG, drawing red links with stroke widths proportional to each link’s `weight` value. Node labels appear in orange text with blue circles, and interactive dragging is enabled via `force.drag`. Data is loaded from an external `data.json` file, which defines the nodes and their connection weights.