A D3.js example constructs a yellow smiley face with animated eyebrows using SVG. The face is composed of a circle for the head, two circular eyes, and a mouth drawn with the `d3.arc` helper. Eyebrows are rendered as rectangles and animated with chained `transition().duration()` calls, moving them up and down repeatedly. The code uses D3 selections and attribute manipulation to build the SVG scene from scratch, with no external data—only hardcoded geometric values for positioning and sizing.