This example demonstrates basic DOM manipulation with D3.js by building an animated smiley face from SVG shapes. It shows how to append and style circles for the face and eyes, rectangles for eyebrows, and a path generated with the `arc` function for the mouth. The eyebrows use chained `transition` calls to move up and down over two-second intervals, while the face is centered using a `g` element with a `translate` transform. The code imports `select` and `arc` from D3 and renders entirely in SVG.