A pie chart visualizes the composition of 150 space cargo shipments by material type, with percentage labels on each slice and a legend listing total units per category. The chart aggregates quantities from a CSV file using `d3.csv` and `d3.rollups`, then renders SVG arcs with `d3.pie` and `d3.arc`. Color encoding uses `d3.scaleOrdinal` with `d3.schemeTableau10`, and slice labels are positioned via `arc.centroid`.