This example shows a tree visualization of smartphone models grouped by brand, with leaf labels displaying model names and branch sums reflecting processor speed. The data is parsed from an inline CSV string. Built with D3.js, it uses `d3.tree` for the layout, `d3.hierarchy` to aggregate numeric values, and `d3.linkHorizontal` for the path generator. Nodes are rendered as circles with white fills and steelblue strokes, while links are gray paths. An interactive zoom, enabled via `d3.zoom`, responds to user gestures to scale the SVG viewport.