Built with D3.js v3, this animated SVG example constructs a cheerful smiley face from basic geometric primitives. The code uses D3 selections and method chaining to append a yellow circle for the head, two eyes, rectangular eyebrows, and an arc-generated mouth. A 2-second transition animates the eyebrow group’s vertical position, creating a subtle winking effect. The example also includes an unused Heatmap class definition, though the visualization itself focuses solely on the SVG composition.