This example shows a scatter plot of the classic Iris dataset, mapping sepal length to the x-axis and petal length to the y-axis, with each species differentiated by a distinct symbol shape. The visualization includes a custom legend that maps species names to their corresponding symbols. The code uses D3 v7 modules such as `scaleLinear`, `scaleOrdinal`, and `symbol` to generate the marks, while a modular `axes` function adds labeled axes. Data is loaded asynchronously from a GitHub-hosted CSV file using `csvParse`, and the plot is rendered into a full-window SVG.