This fork of a brushable scatterplot presents a matrix of scatterplot cells for exploring the classic Iris flower dataset, using four measured traits (sepal and petal length and width). Each cell compares two traits, with points colored by species (setosa, versicolor, virginica) via a simple color map. Using D3 version 3, the code creates a grid of small multiples, with axes ticked and labeled, and implements linked brushing: dragging a rectangle within any cell highlights corresponding points across all other cells, dimming unselected ones. The brush interactions rely on `d3.svg.brush` and callback events, while data is loaded from a local `iris.csv`.