This example demonstrates how to build a simple animated smiley face using D3.js. It shows a yellow circle with eyes, eyebrows, and a mouth, all constructed through fundamental DOM manipulation. The code uses `d3.select` to target the SVG element, `d3.append` to create shapes, and a chained `d3.transition` sequence to animate the eyebrows moving up and down over two-second intervals. The mouth is drawn as an arc using `d3.arc` with specified inner and outer radii. The rendering is SVG-based, with all elements positioned relative to the center of the canvas.