This example creates a visual testbed for D3 using React and SVG rendering. The code generates a 50-by-50 grid of semi-transparent rectangles that tile the full browser window, creating a subtle crosshatch pattern. It then draws eight distinct D3 symbol shapes—such as circles, crosses, and diamonds—spaced horizontally across the viewport using `d3.symbol` and `d3.symbols`. The visualization demonstrates basic D3 selections, data joins, and SVG attribute manipulation with data from `d3.range`.