This example introduces fundamental SVG rendering by generating a grid of 100 vertical rectangles, each 10 pixels wide and spaced 20 pixels apart, across the full browser window height. The code uses native DOM manipulation with `document.createElementNS` and the `http://www.w3.org/2000/svg` namespace to construct the SVG elements dynamically in a loop. It also demonstrates viewport sizing via `window.innerWidth` and `window.innerHeight`, with CSS applied globally to remove margins and hide overflow.