Fork of D3 Transitions
Six colored circles, each tagged with a unique id, appear one-by-one on a light-green SVG canvas using a staggered 2000ms transition that grows their radius from zero to a preset value. A second, faster 500ms linear transition updates the position of existing circles when new data is bound, while a slow transition shrinks circles to zero radius before removal. The example demonstrates D3’s join pattern with explicit enter, update, and exit selections, using `d3.transition`, `easeLinear`, and chained `attr` tweens to choreograph the animation sequence.