This example shows an interactive scatter plot of the Iris dataset, displaying sepal length against petal length with species encoded by marker shape. It uses D3 v7’s `scaleLinear` for axes and `scaleOrdinal` with `symbolsFill` to map species to distinct shapes. A custom-shape legend, built with `d3.symbol`, lists each species. Data is loaded asynchronously via `fetch` and parsed with `csvParse`, then rendered as SVG paths using `d3.symbol` generators.