This example uses D3.js to create a scatter plot of the classic Iris dataset, loaded via a CSV file from a gist. It displays two measurements, petal length along the x-axis and sepal length along the y-axis, as small circles. The code leverages `d3.csv` for data loading and parsing, `d3.scaleLinear` for mapping data values to screen coordinates, and `d3.axisLeft` and `d3.axisBottom` to render the axes. The visualization is drawn as an SVG, sized to fill the browser window, with a fixed margin around the plot.