A smiling face rendered in SVG is drawn with D3.js, using geometric shapes for the head, eyes, eyebrows, and a mouth created with the `d3.arc` path generator. The example demonstrates a looping animation where the eyebrows repeatedly move downward and back upward via chained `transition.attrTween` calls, while the static face elements remain fixed. The code relies on D3 selections and attribute manipulation, with the SVG canvas set to 960 by 500 pixels and centered via a transformed group.