This example visualizes the Iris dataset as a scatter plot of petal length against sepal width, with points colored by species. An interactive color legend allows hovering over a species name to fade all other points and highlight only the selected species. The visualization is built with React and D3 v5, using d3.scaleLinear for axes, d3.scaleOrdinal for the color mapping, and SVG circles rendered through React components. Data is loaded asynchronously from a CSV file via d3.csv.