This visualization presents a pie chart of LEGO sets grouped by theme, using nested arcs to compare price tiers within each category. The chart employs D3.js APIs including `d3.pie`, `d3.arc`, and `d3.scaleOrdinal` to render three concentric rings per slice, showing counts of sets under $50, under $100, and all sets. Labels and connector lines are positioned using arc centroid calculations. The data comes from the `lego-csv` package.