Let's make a face with D3.js!
This example uses D3.js v5 to construct a simple animated face. The SVG rendering starts with a yellow circular face, then adds eyes, eyebrows, and a mouth using an arc path. The eyebrows move up and down through chained transitions, creating a subtle animated expression. The code demonstrates the use of `select`, `append`, `attr`, and `arc` APIs within an SVG container, showing how basic geometric shapes can be assembled into a recognizable character.