An interactive pie chart visualizes iPhone series sales comparisons. Each slice represents a different iPhone model, with its area proportional to sales figures, labeled with sales values and color-coded. A legend lists each series with its corresponding color and sales amount. The visualization is built with D3 v5, using the `pie`, `arc`, `scaleOrdinal`, and `format` APIs, and renders as an SVG. Data is fetched asynchronously from a CSV via a Gist URL.