This example displays a donut chart of aggregated sales data, with each arc labeled by its total value and a legend identifying categories. The visualization also includes tooltips on hover and uses opacity to differentiate segments. Built with React and D3 v2, it loads CSV data and processes it through a custom `TransformChartData` function to sum values by category. The chart is rendered as an SVG using `d3.layout.pie` and `d3.svg.arc`, with color mapping via `d3.scale.ordinal` and interactive legend elements.