This example demonstrates fundamental DOM manipulation with D3.js by constructing a smiley face from SVG shapes. A yellow circle, two eyes, a mouth drawn using the `d3.arc` function, and rectangular eyebrows are all appended to an SVG container. The eyebrows animate by moving up and down through a chained `transition` with `attr` changes, using a two-second duration for each movement. The code uses D3 v5’s `select` and `arc` methods, with the animation running once on load.