Fork of Let's make a face with D3.js!
A yellow circle with black strokes forms a smiley face’s head, featuring two circular eyes, a curved mouth, and rectangular eyebrows. The eyebrows shift downward by 50 units over two seconds and then return to their original position, creating a subtle animated movement. Built with D3 v5, the example uses DOM selection, SVG element creation, and chained `transition().duration()` calls to animate the eyebrow group’s transform. The code also employs `d3.arc` to generate the mouth’s path and `d3.select` for initial setup, rendering entirely in SVG within a 960×500 viewport.