This example builds a yellow smiley face with D3.js, featuring two eyes, a mouth drawn with the `d3.arc` path generator, and eyebrows that animate vertically via chained `transition().attr()` calls over two-second intervals. The face is centered using an SVG `g` element transformed to the viewport’s midpoint, with all shapes positioned relative to that origin. The code uses D3 v5 selections and transitions to demonstrate fundamental DOM manipulation and SVG attribute updates, rendering the animation entirely in the browser.