This example shows a full-screen smiley face rendered as a yellow circle with black outlines, two eyes, and a mouth, centered on the viewport. The face is built entirely with React and SVG elements, using `circle` components for the head and eyes, while a D3 `arc` is imported to construct the mouth’s curved path. The head’s radius dynamically responds to the window’s height, and the layout positions the eyes with fixed offsets, with all coordinates computed from the center of the screen.