This example shows a family tree rendered as a hierarchical node-link diagram using D3.js v5 and SVG. The code uses `d3.hierarchy` and `d3.tree` to compute node positions from nested data, with `d3.select` creating SVG groups, circles, and text labels. Curved link paths are drawn with a cubic Bézier command, while each node’s circle radius encodes a numeric value, and stroke and fill colors come from the data’s `type` and `level` fields. The data is embedded directly in the script as a JavaScript object.