This example shows a scatter plot of the classic Iris dataset, displaying the relationship between petal length and petal width for three species. Each flower is a fixed-radius circle whose color encodes the species (setosa, versicolor, or virginica) through a manual marker function, while the circle’s `rx` and `ry` attributes carry the sepal measurements. The visualization loads data from a remote CSV via `d3.csv`, uses `d3.scaleLinear` with `d3.extent` to compute axes, and renders axes with `d3.axisLeft` and `d3.axisBottom`. Rendering uses SVG appended to the body, with D3's `.join` pattern for circles and styled tick text.