This example uses D3.js v5 to construct an animated face entirely from SVG primitives. It draws a yellow circle for the head, adds two black eyes and rectangular eyebrows, then creates a mouth using an `arc()` path generator. The eyebrows are animated with a two-second `transition()` that shifts them up and down before returning to their original position. The code relies on D3's `select`, `append`, and attribute methods to build and manipulate the SVG scene.