This example shows a four-generation family tree, using a vertical tree layout to display relationships from great-grandparents down to the third generation. The visualization encodes each generation with a distinct color for its circular nodes, and labels each member by name. The code builds the hierarchy with `d3.stratify`, then lays it out with `d3.tree()` and draws the edges using `d3.linkVertical()`. Node relations are defined in a hardcoded data array, and the SVG output includes all text and circles.