Let's make a face with D3.js!
A smiling cartoon face is drawn with SVG shapes, including a yellow circle head, white eyes with black pupils, rectangular eyebrows, and a curved mouth. The face animates through D3.js transitions: the eyes and pupils scale up and down, the eyebrows shift vertically, and the mouth rotates and scales. Using D3 v5, the code builds elements with `select`, `append`, and `attr`, while a series of chained `.transition().duration()` calls create the sequential motion.