This example presents a scatter plot of the classic Iris dataset, visualizing the relationship between sepal length and petal length for three flower species. Each circle is colored according to species, with a categorical color legend positioned in the top-right. Using `d3.scaleLinear` and `d3.scaleOrdinal` with `schemeCategory10`, it builds axes and a legend via custom functions that leverage `axisLeft`, `axisBottom`, and `selectAll(...).join(...)`. Data is loaded as a CSV and parsed in `index.js`.