This interactive tree visualization displays the hierarchy of programming languages, organized by paradigms and domains, with depth and node type encoded through color and shape. Built with D3 v7, it uses `d3.hierarchy` and `d3.tree` to compute the layout, while `d3.linkHorizontal` draws the connecting paths. Node symbols are rendered via `d3.symbol` with diamond, square, and circle shapes for root, internal, and leaf nodes, and a custom tooltip appears on mouse movement.