This example draws a simple, animated face entirely with D3.js v5 and SVG primitives. A yellow circle forms the head, with black circles for eyes and a path created using `d3.arc` for the mouth. The eyebrows are rectangles that animate up and down using chained `transition` calls, each with a 2000-millisecond duration, demonstrating basic declarative animation. The code uses `d3.select` and `d3.append` to build the SVG structure, and the rendering is fully vector-based.