This example uses D3.js v6 to create an animated smiley face, demonstrating fundamental DOM manipulation through chained method calls. An SVG canvas displays a yellow circle with black stroke as the face, containing eyes, eyebrows, and a mouth. The eyebrows are rectangles that automatically animate upward and then back down using sequential `.transition().duration(2000)` calls on a group element. The face is centered using a translate transform, while the mouth is drawn with the `arc()` generator from D3.