A smiley face built with SVG appears centered on a tomato-colored circle, with white eyes, a curved mouth, and eyebrows that animate upward and back down in a continuous loop. The example demonstrates fundamental D3.js DOM manipulation by selecting SVG elements, appending groups and shapes, and using `transition().duration()` to move the eyebrow group. It relies on D3 v5 utilities such as `select` and `arc` for the mouth path, with a fixed 960×500 viewport. The animation runs on page load without user interaction.