This example shows a yellow smiley face built with SVG shapes, where the eyebrows animate upward and then back down in a looping motion. The face is centered using a translated `<g>` group, with circles for the eyes and a D3 arc path for the mouth. It demonstrates fundamental DOM manipulation with D3 v5, using `select`, `attr`, and chained `transition().duration()` calls to move the eyebrow group. The animation runs continuously, shifting the eyebrows vertically by 50 pixels before returning to their original position.