This example demonstrates fundamental DOM manipulation with D3.js by rendering a yellow smiley face with animated eyebrows. The code uses D3 v5 selections and the `arc` generator to draw the mouth, while chained `transition().duration()` calls shift the eyebrows up and down over two-second intervals. Circles and rectangles are appended to an SVG group, positioned relative to the center of a 960x500 viewport. The animation loops implicitly through the chained transitions, and all geometry is defined with fixed pixel constants.