This example demonstrates a simple React component rendering an SVG smiley face using D3’s `arc` generator for the mouth and basic SVG shapes for the eyes and face. The code creates a circular gradient mask, applies it to the face, and positions two black circles for eyes relative to a translated center. Rendering uses React 16 and ReactDOM to mount the component, while D3 v5 provides the `arc` path calculation. The visualization is entirely static, with no interaction or data binding.