A smiling face composed of SVG shapes animates its eyebrows upward over two seconds. The example demonstrates a minimal HTML page setup with D3 v5 and React, rendering a yellow circle for the head, two eyes, and an arc-based mouth. The code uses `d3.select`, `d3.arc`, and `transition().duration()` to animate rectangle elements representing eyebrows, all within a fixed 960×500 SVG canvas.