This example visualizes the classic Iris dataset, plotting petal length against sepal width for individual flowers, colored by species. Hovering over a species in the interactive color legend highlights only the corresponding points, fading the rest. Built with D3 v5 scales and React components, the scatter plot uses the `scaleLinear` and `scaleOrdinal` APIs, and renders SVG circles via custom `Marks` and `ColorLegend` components. Data is loaded as CSV using `d3.csv`.