This animated parallel coordinates plot displays the Iris dataset with four quantitative axes (sepal length/width, petal length/width) and one categorical axis (species). Lines show each flower’s measurements, colored by species using `d3.scaleOrdinal` with `schemeCategory10`. Users brush along any axis via `d3.brushY`, filtering lines dynamically with opacity transitions using `transition().duration(500)`. The code imports from `d3` and `d3-rosetta` for reusable rendering, resizing via `observeResize`, and memoization.