This interactive tree chart visualizes a hierarchical dataset of continents, countries, and companies, with a legend distinguishing each node type by color and shape. The D3.js code constructs collapsible nodes and links, using distinct CSS classes to style continent, country, and company elements. The SVG rendering presents the structure with animated transitions, while the custom styling includes a skyblue background and white link strokes. The tree branches from a root labeled "nontec" down through three levels, with data embedded directly in the script.