A D3.js smiley face is drawn entirely with SVG shapes, using a yellow circle for the head, two black circles for eyes, and a path generated by the `d3.arc` function for the mouth. The code demonstrates fundamental DOM manipulation by selecting the SVG element and appending each shape with explicit attributes for position, radius, and fill. Reactivity is limited to static rendering, with the face centered via hard-coded values derived from the SVG’s width and height. The example uses D3 v5 and relies on `d3.select` for element access.