A treemap visualizes the hierarchical structure of the Flare data set, with nested rectangles whose areas encode either the size or count of each node. The visualization uses D3’s `d3.treemap` layout with `d3.treemapResquarify` tiling, rendering the hierarchy as an SVG. Animated transitions smoothly reshape the treemap when toggling between the "Size" and "Count" aggregation modes. The color scheme is derived from `d3.schemeCategory20`, and the tooltip displays the node’s path and numerical value.