This example shows a smiling face built in SVG whose eyebrows animate up and down. Using D3 v5 and the `d3.arc` and `d3.select` APIs, the code constructs a sky-blue circle for the head, adds eyes, and attaches two rectangles as eyebrows. A path with an arc generator forms the mouth. The eyebrows move via chained `transition.attr` calls over 2-second intervals, demonstrating basic DOM manipulation and selection-based updates without external data.