An interactive family tree for a lineage starting with Sathri, showing descendants like Chandra Shekar and Padmavathi. The visualization uses a collapsible tree layout with D3.js, where clicking a node toggles its children, animating transitions between expanded and collapsed states. The code loads JSON data from `qn_tree.json` and uses `d3.layout.tree()` and `d3.svg.diagonal()` to position nodes and draw curved links. Styling is done via CSS, with nodes as circles and text labels, rendered as animated SVG.