This example demonstrates basic SVG shapes arranged to show color blending through overlapping rectangles. The visualization uses three semi-transparent rectangles in red, blue, and yellow, which combine to create secondary colors where they intersect. The markup is hand-written SVG directly in the HTML file, with dimensions fixed at 500 by 500 pixels. The code also imports D3’s `select` function to update text content in the page, showcasing how D3 can complement pure SVG rendering.