This example visualizes a social network as a force-directed graph, with red circular nodes representing individuals and black lines indicating connections such as “family with” or “friend with” relationships. The graph uses `d3.forceSimulation` with `forceLink`, `forceManyBody`, `forceCollide`, and `forceCenter` to position nodes dynamically. Dragging is enabled via `d3.drag`, and hovering highlights nodes using a CSS class. Data is loaded from a JSON file, and the graph is rendered as SVG elements (`<circle>`, `<line>`, `<text>`), with marker arrows defined in `<defs>`.