This example displays a scatter plot of the Iris dataset, mapping petal length and width as the primary axes while encoding sepal length and width into the size and shape of the circular markers. Each of the three iris species is distinguished by a unique fill color: sky blue, light green, and orange. The visualization uses D3 version 6, loaded via a CDN, and leverages the `d3.csv` loader to fetch the data from a GitHub repository. It builds the plot using `d3.select` to create an SVG, with scales from `d3.scaleLinear`, axes from `d3.axisLeft` and `d3.axisBottom`, and computes data extents via `d3.extent`. The code sets the circle radii, along with `rx` and `ry` attributes, to reflect the additional sepal dimensions, while axis labels are added as text elements.