A smiling face is drawn using React and D3, composed of a yellow circle with a black border, two small circles for eyes, and a curved path for the mouth. The SVG canvas is 960 by 500 pixels, and the face is centered using a transform. The mouth is generated with the D3 `arc` function, which creates an annular sector with specified inner and outer radii and angles. All shapes are rendered as SVG elements, with the background circle and eye positions defined by fixed offsets.