Fork of Let's make a face with D3.js!
This example demonstrates fundamental DOM manipulation with D3.js by constructing a smiley face from SVG primitives, including a yellow circle head, eyes, and a mouth arc. The animation shows the eyebrows moving up and down repeatedly by chaining `transition().duration()` calls on the eyebrow group, which translate vertically. The code builds the face using `d3.select`, `svg.append`, and `d3.arc` to generate the mouth path, with all elements arranged via absolute coordinates. The animation runs automatically on load, cycling the eyebrow position every two seconds.