A smiling face made of SVG shapes serves as a compact demonstration of combining React with D3. The example renders a yellow circle with a black stroke, two eye circles, and a mouth path generated using the `d3.arc` function with specified inner and outer radii. React 16 manages the component structure, while D3 v7 provides the arc generator that produces the mouth's curved path. All shapes are drawn in an SVG coordinate system with fixed dimensions.