This example shows a scatter plot of the Iris dataset, encoding sepal length on the x-axis and petal length on the y-axis. Species is represented by three distinct shapes via a `scaleOrdinal` with `symbolsFill`, and a custom legend displays the shape-to-species mapping. The code builds reusable modules for axes and legends, loads data with `csvParse` from a remote URL, and renders the visualization using D3 v7’s data-join pattern with `selectAll` and `join`.