This example renders a yellow smiley face that fills the entire browser window. The face is composed of SVG circles for the head and eyes, with a mouth drawn using a D3 arc path generator. Using React components, the visualization positions all elements relative to the viewport center, calculating the head radius from the window height. The code imports React and ReactDOM for rendering and the `arc` function from D3 v7 to define the mouth’s curved shape, with stroke widths and offsets parameterized for scalability.