This example shows a yellow smiley face with two eyes, moving eyebrows, and a curved mouth, rendered as SVG shapes. The eyebrows shift upward and then return to their original position using chained `transition().duration()` calls. The code builds the face with D3 selections and shape generators, including `select`, `arc`, and attribute setters like `.attr()`, positioning elements via `translate` transforms on a centered group. The face is drawn entirely through D3’s DOM manipulation, with no external data source.