A brushable scatter plot matrix displays the Iris dataset across four morphological traits, with each cell showing the relationship between a pair of features and colored points representing three Iris species. Users can drag a rectangular brush over any scatter plot to highlight corresponding data points across all other plots simultaneously, while hovered circles enlarge and reveal a tooltip. Using D3 v4, the visualization employs `d3.scaleLinear`, `d3.axisBottom`, `d3.axisLeft`, `d3.brush`, and `d3.scaleOrdinal` to render the SVG grid, with animated transitions for circle radius and opacity.