This pie chart visualizes aggregated OS user data for Android, iOS, and BlackBerry OS. It uses D3 v6 with `d3.pie` and `d3.arc` to generate slices with corner radii, and `d3.scaleOrdinal` for color mapping. Percentage labels are placed at each slice centroid, and a legend identifies the categories. The data comes from a CSV file containing yearly OS usage statistics from 2009 to 2023.