A yellow smiley face, rendered with SVG shapes, demonstrates fundamental DOM manipulation and animated transitions in D3.js. The example builds the face using appended `circle`, `rect`, and `path` elements, with the mouth generated via the `d3.arc` generator. Both eyebrows, created as rectangles, move up and down through chained `transition()` calls on their containing group, each lasting two seconds and alternating between two vertical offsets. The code uses D3 v5 selection methods and `attr` to position elements, with no external data source, purely illustrating programmatic shape creation and animation.