This example demonstrates fundamental SVG shapes and their rendering behavior within an HTML document. The code uses raw SVG APIs to draw a red circle, a yellow rectangle with a blue stroke, a diagonal line, and a black polyline path, all positioned on a 960 by 500 canvas. It shows how z-index is implicitly determined by element order, as the shapes are layered in the order they appear. The path uses the `d` attribute with absolute coordinates to create a multi-segment line, while the rectangle demonstrates the use of the `stroke` and `stroke-width` attributes for visual styling.