A scatter plot visualizes the Iris dataset, mapping sepal length to the x-axis and petal length to the y-axis. Points use distinct shapes—rendered via d3.symbol and scaleOrdinal with symbolsFill—to encode the three species, with a custom shape legend labeling each category. The code loads the CSV with d3.csvParse, converts numeric fields, and builds the chart using d3.scaleLinear axes and d3.scaleOrdinal for shapes.