This example shows a smiley face built from SVG circles and an arc-shaped mouth, centered in a 960-by-500 viewport. The face uses yellow fill with a black stroke for the head, fixed eye positions, and a mouth drawn with D3’s `arc()` function. React renders the SVG elements, with geometry parameters like `eyeOffsetX` and `mouthRadius` computed from the canvas dimensions. The code mixes inline SVG markup in `index.html` with a separate React component that uses D3’s arc API for the mouth path.