This interactive visualization displays a collapsible tree diagram using d3.layout.tree, with nodes rendered as SVG symbols (circles, crosses, or diamonds) and links colored by a level property from the embedded JSON data. The code loads d3 v3 from a CDN and uses d3.svg.diagonal for curved edges, along with d3.svg.symbol to vary node shapes based on value thresholds. The tree includes hardcoded family hierarchy data, with fixed node depths and margin-based layout, though no collapse/expand behavior is implemented in the shown script.