A smiling face rendered in SVG shows two black eyes with white highlights that dart side to side, while a static arc forms the mouth. The animation uses chained `transition` calls on the eye highlight circles to shift their `cx` attributes over 1600 and 1400 milliseconds. Built with D3 v5, the code appends circles and a path using `d3.select`, `arc`, and shape helpers, with no external data source.