This example displays a pie chart of mean maximum temperatures for three different zip codes, using weather data from CSV files. The D3 v3 pie layout calculates the arc segments, while d3.svg.arc generates the SVG path shapes for each slice. The code nests and aggregates the data with d3.nest and d3.mean, then assigns distinct colors based on the zip code key. The chart is rendered as SVG with a single series, and each slice’s size reflects the temperature average for that region.