This hierarchical tree visualization maps programming languages by paradigm and family, showing the relationships from root categories down to individual languages. It uses D3 v7’s `stratify` and `tree` APIs to process CSV data and compute the layout, while custom `symbol` shapes (circle, square, diamond, triangle) and an ordinal color scale distinguish each depth level. Interactive tooltips display node names and layer types on hover, with a legend explaining the four tiers. The visualization renders as SVG with horizontal link paths connecting nodes.