This example shows a scatter plot of iris flower measurements, encoding sepal length on the x-axis, petal length on the y-axis, and species as point shapes. It loads the Iris dataset from a CSV file and parses it with `d3.csvParse`. The visualization uses `d3.scaleLinear` for positional scales and `d3.scaleOrdinal` with `d3.symbolsFill` to map species to distinct marker shapes. Axes and a custom shape legend are drawn using D3 selections, with `d3.axisLeft`, `d3.axisBottom`, and `d3.symbol` generators.