This example shows the Iris dataset rendered as four linked histograms, one for each numeric column. Brushing any histogram cross-filters the other charts, with highlighted bars showing data points that fall within all active brush selections. The visualization is built with React managing state and lifecycle via `useState` and `useEffect`, while D3 v7 handles SVG rendering, `brushX` interactions, and animated bar transitions. A `ResizeObserver` hook tracks container dimensions for responsive re-rendering.