Hundreds of small, semi-transparent circles continuously stream inward from the top and bottom edges, converging at the center before dispersing outward again in a looping, decorative motion. The animation is generated entirely with D3 v3, using chained `transition()` calls over 2-second durations to animate each circle’s `cx` and `cy` attributes with a linear ease, then removing each element after its animation completes. Random colors are assigned via a custom `colorPicker` function, while circle starting positions and target offsets are determined by `Math.random()`. A `setInterval` spawns a new circle every 20 milliseconds, capped at 1,000 total per loop, which then repeats indefinitely.