This example demonstrates a reusable scatter plot visualizing the Iris dataset, with species distinguished by different D3 symbol shapes (circles, crosses, and diamonds). It maps petal width and sepal length to x/y positions using `d3.scaleLinear`, and uses `d3.scaleOrdinal` to assign symbols to species. The code employs `d3.axisLeft` and `d3.axisBottom` for axes, and renders the marks as SVG paths generated by `d3.symbol`. Data is loaded asynchronously via `d3.csv` from a GitHub gist.