This example shows a simple smiley face drawn with D3.js, using a yellow circle for the head, two black circles for eyes, and an arc path for the mouth. It renders to an SVG element with fixed dimensions. The code imports `select` and `arc` from D3 v5, uses `svg.append` to create each shape, and sets attributes like `fill`, `r`, and `cx`/`cy` directly. The mouth’s path is generated by the `arc()` function with specified start and end angles. The page loads D3 from a CDN and runs the script in a React-based setup.