This example builds a smiley face from basic SVG shapes using D3.js, demonstrating core DOM manipulation and selection techniques. The code appends a yellow circle for the head, two eyes, rectangular eyebrows, and an arc-based mouth inside a centered group element. The eyebrows animate by chaining `transition` calls with a two-second duration, moving them upward and back down in an infinite loop. The implementation uses D3’s `select`, `append`, `attr`, and `arc` APIs to construct and position all elements.