This example demonstrates fundamental SVG shapes directly in an HTML page, including a pair of concentric circles, a diagonal line, a curved path, and a filled rectangular path. The code uses the native SVG API within an inline `<svg>` element, with shapes defined by elements such as `<circle>`, `<line>`, and `<path>`. No external libraries are employed, and the rendering relies entirely on static SVG markup with attributes like `cx`, `r`, `stroke`, and `fill` to control appearance.