This example animates a smiley face in SVG, moving its eyebrows up and down in a repeating two-second cycle. The face is constructed using D3.js v5 to append and position geometric shapes—circles for the eyes, rectangles for the eyebrows, and a path created with the `arc()` generator for the mouth—within a central group. The animation relies on chained `transition().duration(2000)` calls on the eyebrows group to alternate its vertical transform, demonstrating fundamental DOM manipulation with D3.