This example visualizes the iris dataset as a scatter plot, mapping sepal length to the x-axis and petal length to the y-axis. Different species are distinguished through distinct symbol shapes, with a legend identifying each category. The visualization uses d3.csvParse to load and parse the data, then applies d3.scaleLinear for positioning, d3.scaleOrdinal with symbolsFill for shape encoding, and d3.axisLeft and d3.axisBottom for axes. A custom shape legend renders the categorical mapping for species.