A smiley face drawn in SVG animates as its eyebrows bounce upward and settle back down. The example demonstrates fundamental D3.js DOM manipulation by constructing the face from appended shapes—circles for the eyes and head, rectangles for the eyebrows, and a path generated with the `arc` helper for the mouth. A chained `transition` with a two-second duration moves the eyebrow group twice, creating the animation. The code uses D3 v5 selections and attributes on a static SVG canvas.