This example visualizes supermarket order data as a treemap, though the current implementation renders each data row as a fixed 50×50 cell in a diagonal layout rather than computing hierarchical rectangles. It loads CSV data via `d3.csv` and uses `d3.treemap()` for layout, though the layout result is not actually applied to the cells. The SVG output is appended to a `#treemap` div, with rectangles and text labels showing partner country names. The page uses D3 v7 and relies on dynamic window dimensions for the chart size.