This example renders a smiling face as a static SVG with animated eyebrows. A yellow circle forms the head, with blue eyes, a mouth created via `d3.arc()`, and two rectangles for eyebrows that move upward and back down using chained `transition().duration()` calls. The visualization uses D3 v7’s `select`, `append`, and `attr` methods to build the SVG elements, with coordinates computed from the SVG’s width and height attributes. The eyebrows repeatedly animate between two vertical positions, creating a playful, looping motion.