This example renders a smiling cartoon face as a static SVG scene, but adds a looping animation that moves the eyebrows up and down over time. The face is constructed using D3.js primitives: a yellow circle for the head, smaller circles for the eyes, rectangles for the brows, and a path generated with `d3.arc` to form the mouth. The code uses D3 v5’s selection and transition API to animate the eyebrow group’s transform attribute, creating a simple, expressive effect.