This example shows a hierarchical tree diagram built from a CSV file listing parent-child relationships between defect types and priority categories. The visualization uses D3.js’s `d3.layout.tree` and `d3.svg.diagonal` to position nodes and draw curved links, with SVG rendering for circles and labels. The data, loaded via `d3.csv`, is converted from a flat structure into a nested tree and displayed with a fixed-depth layout, where each level represents a different category of items.