This example shows a force-directed layout with 200 circles organized into 10 distinct clusters, each rendered in a different color from the `d3.schemeCategory20` palette. The circles are separated into their groups by the `clustering` custom force, while the `collide` function, which uses a quadtree, prevents overlap both within and between clusters. The visualization is built with D3 v4, uses the `d3.forceSimulation` API for physics, and renders via SVG. The `ticked` callback updates each circle’s `cx` and `cy` attributes as the simulation runs.