A yellow SVG smiley face with black facial features demonstrates D3.js’s core DOM manipulation and transition APIs. The head, eyes, eyebrows, nose, and mouth are built by appending SVG circles, rectangles, and arcs via `d3.select` and `d3.arc`. Concurrent two-second `transition` chains animate the eyebrow group upward, eyeballs sideways, nose sideways, and mouth downward before returning all groups to their original positions. The example is rendered entirely in SVG and uses D3 v5 from a CDN.