This example displays a classic yellow smiley face rendered as an SVG, with black circular eyes, a thick black stroke outlining the face, and a mouth drawn as an arc using the d3.arc() API. React manages the component structure, while D3 v5 provides the arc generator for the mouth path. The code includes a red diagonal line crossing the face, created with an SVG line element, showing how D3 and React combine to layer static shapes.