This radial tree example visualizes a three-level hierarchy of programming languages, categorized first by paradigm (Compiled, Interpreted, Functional) and then by individual language names. Built with D3.js v7, it uses the `d3.hierarchy`, `d3.tree`, and `d3.linkRadial` APIs to compute the layout, with each node’s shape and color (circle, square, triangle; black, blue, green) varying by depth. Custom SVG paths are drawn for links and nodes, and text labels are positioned according to the node’s angle.