Let's make a face with D3.js!
A smiley face with animated eyebrows demonstrates basic DOM manipulation with D3.js. The visualization renders SVG shapes—a yellow circle, eyes, rectangular eyebrows, and an arc-based mouth—centered on a 960×500 canvas. Using `d3.select` and `d3.arc`, the code constructs each facial feature programmatically. A chained `transition` with 2000-millisecond durations moves the eyebrow group upward and back, creating a blinking-like motion. The example showcases fundamental D3 v5 selections, attribute setting, and animation without external data, relying purely on geometric constants for positioning.