This example demonstrates fundamental SVG shapes using two circles, one with default styling and one filled red. The code uses plain HTML and inline SVG elements—specifically `<svg>` and `<circle>`—without any JavaScript or CSS file. It shows how to define circle positions with `cx` and `cy` attributes and set their radius with `r`, while the `fill` attribute controls color. The rendering occurs directly in the browser’s SVG renderer, requiring no external libraries or frameworks.