Hello HTML
This animation demonstrates how D3.js can manipulate SVG elements to create a moving smiley face. The yellow face with eyes, eyebrows, and a mouth is drawn using basic shapes and a d3.arc path. Eyebrows animate up and down through chained d3 transitions that adjust their transform attribute over two-second intervals. The example uses D3 selections to append circles, rectangles, and an arc-generated path within a centered group.