Making a bar chart
A smiley face rendered in SVG shows animated eyebrows that move up and down. The D3.js code uses `select` and `append` to build circles for the face and eyes, rectangles for eyebrows, and a path with an arc for the mouth. A `transition` with a 2000-millisecond duration animates the eyebrow group’s transform, shifting it vertically and back. The example demonstrates fundamental DOM manipulation with D3 v5, using static SVG attributes and chained transitions to create a simple looping animation.