This example displays the Iris dataset as a scatter plot, encoding petal width on the x-axis, sepal length on the y-axis, and species as distinct shapes using D3’s `symbol` API. It uses `scaleLinear` for axes, `scaleOrdinal` to map species to symbol types, and `axisBottom`/`axisLeft` for ticks. The plot is rendered as an SVG, sized to the full window, and loads data from a CSV URL via `d3.csv`. The reusable `scatterPlot` function configures margins, symbol size, and value accessors.