This example demonstrates the foundational building block of SVG graphics: a single green circle rendered on a blank canvas. The circle is positioned at coordinates (150, 150) with a radius of 150 pixels, filling the space with a flat green color. The visualization uses raw SVG markup within an HTML page, explicitly setting the canvas dimensions to 400 by 400 pixels. No external libraries or JavaScript are required, as the circle is defined entirely through static SVG elements like `<svg>`, `<circle>`, and the `cx`, `cy`, `r`, and `fill` attributes.