An interactive HTML page displays the BMI distribution across occupations as a tree graph, with the SHL dataset transformed from CSV into a three-level hierarchy of BMI categories and individual occupations. The d3.v6 library builds the layout, while SVG rendering handles the nodes and links, using colored rectangles and circles to distinguish depths and animated tooltips to reveal data on hover. The code relies on custom functions like `csvToHierarchy` and the d3 `tree` layout, with styling applied through a separate CSS file.