This example shows a hierarchical tree visualization with collapsible nodes, where each node is rendered as a colored box. The tree displays data from a JSON file, with node colors representing different types. The visualization uses D3.js v3 to compute the tree layout and render SVG rectangles for nodes and curved paths for links. The implementation includes animated updates when nodes are expanded or collapsed, and supports zooming and panning via D3's zoom behavior. Tooltips provide additional node information on hover.