This example demonstrates a force-directed network layout, visualizing a small set of nodes and their connections with interactive dragging. The graph dynamically arranges connected circles using a physics simulation, cleanly separating linked nodes while repelling them from one another. The visualization is built with D3 v7, using `d3.forceSimulation` together with its `forceLink`, `forceManyBody`, and `forceCenter` components. The SVG output renders nodes as circles with labels and edges as straight lines, with positions updated on each simulation tick. The code also includes a guard that filters out any edges referencing non-existent nodes, ensuring the structure remains valid.