Fork of Hello HTML
This example renders a smiley face as an SVG composed of D3-generated shapes, drawn with React and D3 v6. The face uses three circles for the head and eyes, plus an arc path created via `d3.arc()` for the mouth, all centered on a 960×500 viewport. The `arc()` function defines the mouth’s inner and outer radii and its start and end angles, while React’s `ReactDOM.render()` mounts the component tree. The yellow head and black stroke mimic a classic emoji, with positioning handled by JSX attributes and a transform group.