A smiley face drawn with D3.js animates its eyebrows in a looping vertical motion. The SVG face uses simple shapes—circles for the eyes and head, rectangles for eyebrows, and an arc path for the mouth—all positioned relative to a centered group. D3’s selection and transition methods, including `transition().duration()`, move the eyebrow group up and down repeatedly. The code demonstrates fundamental DOM manipulation by binding data-less SVG elements and applying chained transitions without external data sources.