This example visualizes a hierarchical tree of muscle car models—from the root "Muscle Cars" down to brands like Ford and Dodge, and their specific models such as Mustang, Torino, Charger, Challenger, Hellcat, and SRT. The tree uses colored rectangular nodes for different type levels and includes a zoom-and-drag interface. It renders as an SVG using D3 v3’s `d3.layout.tree` for layout and `d3.behavior.zoom` for interaction, with node and link styling from custom CSS. The data is loaded from a static JSON file via `d3.json`.