A network graph displays nine billionaire nodes and eight weighted links, using `d3.layout.force` to simulate a physics-based layout with gravity, distance, and charge parameters. The SVG renders each person as a red circle with a dark outline and a black-on-green text label, while link thickness reflects each connection’s weight from the `graph.json` data. Nodes are draggable via `force.drag`, and the tick handler updates line endpoints and node transforms. The visualization uses D3 v4’s force layout and SVG elements, with styles defined in CSS for links and node text.