A yellow smiley face rendered in SVG shows how React and D3 can be combined to draw simple shapes. The face uses two circles for eyes and a D3 `arc()` generator for the mouth, with all elements positioned relative to a central transform. React manages the SVG markup, while D3 provides the path calculation for the mouth arc. The example demonstrates a minimal setup using React 17, ReactDOM, and D3 v7, with static data encoded directly in the component.