This example visualizes the classic iris dataset as a scatter plot, mapping sepal length to the x-axis and petal length to the y-axis, with overlaid shape-based categorization for the three iris species. A custom legend with distinct symbol shapes identifies the species. The visualization is built using D3 v7, leveraging its `scaleLinear`, `scaleOrdinal`, `symbolsFill`, and `symbol` APIs for coordinate mapping and shape generation, with axes and labels added via `axisLeft` and `axisBottom`. Data is fetched and parsed from a remote CSV file using D3’s `csvParse`.