This network graph visualizes relationships among six people using a force-directed layout. It loads data from an external JSON file specifying nodes and weighted links, then renders nodes as orange circles with name labels and green lines for connections. The example uses D3 v4 and v2 APIs simultaneously, relying on `d3.layout.force` to simulate the physical forces that position the nodes. Link thickness scales with the square root of each connection’s weight, while a tick handler updates the SVG elements’ positions during the simulation.