This example visualizes a family tree as a tidy tree diagram, using circle size to represent a numeric value and color encodings to convey two categorical attributes (type and level) via stroke and fill. The data is a static JavaScript object nested to show parent-child relationships. Built with D3 v5, the code uses `d3.tree()` and `d3.hierarchy` to compute node positions and renders the SVG output with curved links via path `C` commands. Node labels are positioned to the left or right depending on whether a node has children.