This example shows three large colored rectangles filling an 800-pixel-tall SVG canvas: a red area on the upper left, a blue area on the lower left, and a green vertical strip on the right. The page uses only the SVG API directly, with no JavaScript libraries, to draw static shapes via `<rect>` elements. The rendering is fixed to a 960-by-800 viewport with no interaction or animation, demonstrating basic SVG layout and coordinate positioning.