This example renders a smiley face using React components that generate SVG circles and a D3 arc path. The `BackgroundCircle`, `Eyes`, and `Mouth` components receive numeric parameters for radius, offsets, and stroke width, which are assembled within an SVG group translated to the canvas center. The mouth is created with the `d3.arc` API, producing a half-circle path. The final graphic demonstrates layered SVG primitives and D3 geometry within a React rendering pipeline.