This example shows a yellow smiley face built with SVG, whose eyebrows animate by moving up and down in a repeating two-second cycle. The face is centered using a translation transform on a group element, with circles for the eyes and an arc path for the mouth. The code uses D3 v5’s `select`, `arc`, and `transition` APIs to construct the shapes and drive the eyebrow motion, with dimensions and offsets defined as constants. The animation runs once on load, moving the shared eyebrow group downward, then back to its original position.