This example renders a large yellow smiley face that fills the browser window, with its features dynamically positioned relative to the viewport center. The face is drawn using React components that output SVG elements, including circles for the head and eyes and an arc path for the mouth. The arc is created with d3.arc, using inner and outer radii and a start angle of zero with an end angle of pi over two. The layout recalculates the face’s dimensions based on `window.innerWidth` and `window.innerHeight`, scaling the head radius relative to the window height.