This example demonstrates fundamental DOM manipulation with D3.js by constructing an animated smiley face in an SVG. The code uses `d3.select` to append circles for the eyes, rectangles for the eyebrows, and an `arc()` generator for the mouth. A chained `transition()` with a 2000-millisecond duration moves the eyebrows up and down repeatedly, showcasing simple animation. The face is centered with a `g` element, and all shapes are drawn using D3’s SVG helper methods.