This example demonstrates how to integrate React with D3 to render animated SVG rectangles. The React component `App` defines an SVG canvas with a group element containing multiple blue rectangular bars positioned at varying x and y coordinates. An SVG `<animateTransform>` element animates the group by translating it vertically from 0 to 500 pixels over a one-second loop. The code imports `React`, `ReactDOM`, and the `rect` function from D3, though only the SVG rendering is used, without data binding.