This example shows a simple yellow smiley face composed of SVG shapes, rendered via React and D3. The face uses a circle for the head, two circles for eyes, and an arc path generated with `d3.arc` for the mouth, all positioned relative to the SVG center. React’s `App`, `Face`, `Eye`, and `Mouth` components render static markup, while the mouth’s path comes from `arc().innerRadius()`, `.outerRadius()`, and fixed start and end angles. The code imports `arc` from d3 and renders the scene with `ReactDOM.render`.