This example shows a scatter plot of the Iris dataset, encoding sepal length on the x-axis, petal length on the y-axis, and species with different filled symbols. It uses d3.csvParse to load and parse the data, then d3.scaleLinear and d3.scaleOrdinal with d3.symbolsFill to map values to positions and shapes. Custom axis and legend modules, built with d3.axisLeft, d3.axisBottom, and d3.symbol, render labeled axes and a shape legend.