This tree graph visualizes the hierarchical relationship between smartphone brands and their models, using processor speed as a secondary attribute for each leaf node. The d3.stratify layout transforms flat JSON data into a hierarchy, which is then rendered as horizontal links and circles connected by the d3.tree layout. Nodes are positioned using the tree layout’s x and y coordinates, with d3.linkHorizontal generating smooth curved paths for the edges. The SVG canvas displays each phone model as a labeled circle, with brand names appearing as parent nodes, all styled with steelblue fills and white strokes.