This example visualizes the Iris dataset as a scatter plot, mapping petal length along the x-axis and sepal length along the y-axis. Each circle represents one flower, with no color or categorical encoding. The code loads data via `d3.csv` from a remote GitHub gist, parses numeric fields, and uses `d3.scaleLinear` with `d3.extent` to set the domains. Axes are rendered using `d3.axisLeft` and `d3.axisBottom`, and the plot is drawn as SVG circles with a fixed radius within a full-window viewport.