A force-directed graph visualizes three nodes connected by two links, using D3's `d3.forceSimulation` with `forceManyBody`, `forceLink`, and `forceCenter` to compute positions. The SVG circles and lines update on each simulation tick. The example also demonstrates a zoom interaction by appending a circle to an SVG with `d3.zoom`, though the zoomed circle is independent of the force layout. Rendering uses SVG elements selected and manipulated via D3's `select` and data joins.