This example demonstrates a minimal force-directed graph, showing four nodes and three directed links loaded from a CSV file. It relies on D3 version 7’s legacy `d3.layout.force` API to calculate node positions and update SVG circle and line elements on each tick. The data is read asynchronously with `d3.csv`, and the layout is initialized with a fixed width and height. Node drag behavior is enabled through `force.drag`, though no styling is applied to the elements beyond the default.