This example shows a scatter plot of iris flower measurements, with sepal length on the x-axis and petal length on the y-axis. Each point uses a distinct symbol shape to encode the species of the flower, and a custom legend explains the shape-to-species mapping. The visualization loads CSV data from a remote GitHub repository, parses it with `d3.csvParse`, and renders the chart using modular D3 v7 functions such as `scaleLinear`, `scaleOrdinal`, `symbolsFill`, `axisLeft`, and `axisBottom`. The code organizes its layout through reusable modules for axes, scatter plot, and a shape legend.