A smiling face is drawn with a yellow circle, black-outlined eyes, and a curved mouth, all composed from SVG primitives. The example is built with React and D3, where variables like `eyeOffsetX`, `eyeRadius`, and `mouthRadius` control facial feature placement and size. D3’s `arc` function generates the mouth’s path, while React fragments group eye circles. The SVG output is assembled via a custom `Face` component that layers a background circle, eyes, and mouth inside a transformed group.