This example visualizes a social network graph, showing friendships among eight people with red circular nodes and directed black links. It uses force simulation via `d3.forceSimulation` with `d3.forceLink`, `d3.forceManyBody`, and `d3.forceCollide` to position nodes, while dragging is enabled through `d3.drag`. The SVG renders from JSON data containing nodes and links with relationship attributes. Hovering a node triggers the CSS class `nodeHover`, which thickens the node’s green stroke.