This example shows a simple yellow smiley face built from React components, with a circular background, two black eyes, and a smiling mouth. The face is centered within an SVG canvas created by the `FaceContainer` component, which translates the drawing to the middle of the viewport. Each facial feature is a separate React component—`BackgroundCircle`, `Eyes`, and `Mouth`—rendered as SVG elements. The mouth uses `d3.arc` from d3.v7 to generate a path with a specified inner radius and angular range, while the SVG circle elements define the head and eyes based on numeric props passed from the main `App` component.