This example demonstrates the basic building blocks of SVG graphics by rendering two circles on an HTML page. It shows how SVG elements like `<circle>` are placed using the `cx` and `cy` attributes and sized with the `r` attribute. The first circle uses the default black fill, while the second is explicitly filled with red via the `fill` attribute. The code uses raw SVG markup embedded directly in an HTML document, with no external libraries, relying solely on built-in web standards for rendering and styling.