This example visualizes the Iris dataset with a scatterplot, mapping sepal length to the x-axis, petal width to the y-axis, and encoding species by color, while also scaling point radius by sepal length. The code uses D3.js v3 to construct an SVG, applying linear scales for positioning and radius, and a category10 color scale for categorical grouping. Axes are generated with d3.svg.axis, and the data is loaded as CSV from a remote GitHub source. The visualization highlights the relationship between measurements and species clusters without interaction or animation.