A smiling face built with SVG shapes animates as its rectangular eyebrows rise and fall in a looping two-second cycle. The example demonstrates core D3.js v5 DOM manipulation, using d3-selection methods like `select`, `append`, and `attr` to construct the face, and `transition` with a duration to move the eyebrow group. Rendered at 960 by 500 pixels, the face centers itself and draws a yellow circle, eyes, and an arc-based mouth using d3-shape's `arc`.