This example shows a simple smiley face built from SVG shapes within a React component, using D3.js to generate the mouth arc. A yellow circle with a thick black stroke forms the head, while two black circles serve as eyes positioned symmetrically around the center. The mouth is created with the D3 `arc` function, which defines an inner and outer radius plus start and end angles to produce a semicircular path. The code uses React 17 and D3 v7, rendering everything to a fixed 960×500 SVG canvas.