This example shows 300 circular nodes grouped into three distinct clusters, each with its own radial gradient color scheme. The visualization uses a force-directed simulation with `d3.forceSimulation` and a custom cluster force to keep nodes near their group’s center, while `d3.forceCollide` prevents overlap by applying padding based on node radius. The nodes are drawn as SVG circles, with each cluster’s color derived from a linear scale mapped to a radial gradient, creating a smooth visual distinction. The code defines three separate radial gradients and assigns them based on the node’s cluster value, while the custom cluster force adjusts node positions relative to a designated cluster center.