This brushable scatterplot matrix displays the classic Iris dataset, showing pairwise relationships between four flower measurements. The visualization is built with D3 v7 and rendered as SVG, featuring histograms along the diagonal and colored scatterplots for the three Iris species elsewhere. Users can brush any cell to highlight selected data points across all plots, with unselected points dimming to reveal correlations. The implementation uses d3.brush for selection, d3.scaleLinear for axes, and d3.bin for histograms.