This example displays a pie chart visualizing student marks based on hours spent studying, with each slice labeled by GPA value. It uses D3.js v5 to load CSV data from a GitHub gist, compute pie segments with `d3.pie` and `d3.arc`, and render SVG paths and text. A legend pairs study hours with GPA values, colored via `d3.scaleOrdinal`. The visualization updates dynamically after fetching and parsing the data asynchronously.