This example shows a simple animated smiley face with eyebrows that move up and down. Built with D3.js v5, it renders an SVG face using basic shapes like circles, rectangles, and an arc for the mouth. The eyebrows animate through chained `transition()` calls that repeatedly adjust their vertical position. All elements are positioned relative to the SVG center using a group transform, and the code imports specific utilities such as `select` and `arc` from the D3 library.