This example shows a scatter plot of the Iris dataset, mapping sepal length on the x-axis and petal length on the y-axis, with points colored and shaped by species. A custom shape legend displays the species categories. The visualization uses D3 v7 APIs including `scaleLinear`, `scaleOrdinal`, and `symbol` to render the marks, with axis and legend components built as reusable functions. The dataset is loaded as a CSV from a GitHub URL, parsed with `csvParse`, and numeric columns are converted before rendering. The plot updates responsively to the window size.