A cheerful yellow face built from SVG shapes appears centered in the viewport, with two black eyes and a curved mouth. The example demonstrates basic D3.js shape generation using the `select` and `arc` APIs. Circles define the head and eyes with fixed pixel coordinates, while the mouth uses `d3.arc` with an inner and outer radius and a half-circle angle range. The SVG canvas is 960 by 500 pixels, and all elements are positioned relative to its dimensions.