This example demonstrates a scatter plot visualizing the Iris dataset, where sepal length is mapped to the x-axis and petal length to the y-axis. The chart uses D3 v7 APIs including `scaleLinear`, `scaleOrdinal`, `symbol` with `symbolsFill` to render distinct shapes for each iris species, with a custom shape legend. Data is loaded as CSV and parsed with `csvParse` from a remote gist. The implementation is modular, with separate functions for drawing axes, the scatter plot, and the legend.