This example demonstrates a minimal D3 v7 force-directed graph with three nodes connected by two links, rendered as SVG circles and lines. The simulation uses `d3.forceSimulation` with `forceManyBody`, `forceLink`, and `forceCenter` to position the nodes, while tick events update the circle coordinates and line endpoints. The data is hardcoded as a small array of node and link objects, and the visualization starts with no styling beyond basic radius and stroke attributes.