This example shows the amount of protein in grams present in various cereals as a pie chart, with a legend identifying each cereal and its corresponding protein value. The visualization loads a CSV dataset from a GitHub gist using `d3.csv` and renders the chart as SVG. It uses `d3.pie` to compute the arc angles, `d3.arc` to generate the path segments, and `d3.scaleOrdinal` to assign colors from a fixed palette. A separate legend group is built by appending rectangles and text labels for each data entry.