This example shows a force-directed network graph where nodes and links are positioned using D3’s physics simulation. The visualization uses `d3.forceSimulation` with link, charge, and center forces to arrange connected nodes, which are rendered as fixed-size circles and joined by gray lines. It loads JSON data from a remote GitHub repository and applies D3 v4, with the layout updating via the simulation’s `tick` event to adjust node coordinates. The design is minimal, with no interactive behavior.