A smiling face drawn with SVG shapes in D3.js animates its eyebrows upward and back down over two seconds. The example demonstrates fundamental DOM manipulation using D3’s `select` and `append` methods to build circles for eyes, rectangles for eyebrows, and an arc-based path for the mouth. A chained `transition` with a two-second duration moves the eyebrow group’s `transform` attribute, showing how to animate SVG elements with D3’s transition system.