This example visualizes a hierarchical tree of physics topics, showing the breakdown from general categories like Classic and Modern Physics down to specific subfields. A static, non-interactive layout renders the data as a series of linked nodes, with each link’s color corresponding to the `level` property of the descendant node. The visualization is built using the D3.js v6 library, employing the `d3.tree()` layout algorithm on hierarchical data and using SVG paths for the links. The tree data is embedded directly in the source code as a JavaScript object.