A smiley face is drawn as a full-screen SVG, with its head, eyes, and mouth created from geometric shapes. The face fills the viewport, with a yellow circle for the head, blue eyes with white highlights, and a curved arc for the mouth. The implementation uses React to render the SVG elements and D3 v7’s `d3.arc` and `d3.line` APIs to generate the mouth, dimple, and nose paths. All coordinates are calculated from the window’s inner width and height, making the visualization responsive.