A grid of eighteen randomly generated smiley faces animates in place, with each face's features—eye size and position, mouth radius, and stroke width—randomizing every 300 milliseconds. A toggle button pauses or resumes the regeneration. Built with React and D3 v5, the example composes reusable SVG components for the face, eyes, mouth, and background circle, using D3's `arc` generator to draw the smile shape.