This example shows a simple yellow face with two eyes and an open mouth, rendered as SVG shapes and animated with D3 transitions. The code uses D3 v7's `select` and `arc` functions to build the shape, with a circle for the head, two circles for eyes, and an arc path for the mouth. One eye animates vertically up and down using chained `transition()` calls with `attr` updates over 1000ms durations, while the other eye and mouth remain static. The SVG canvas is 800 by 400 pixels, and the drawing is centered via a `g` element transform.