A grid of 300 white circles forms a static horizontal row that animates vertically as a sine wave, creating a fluid, undulating pattern across a black background. The animation uses D3 v7's `d3.timer` to continuously update each circle's `cy` attribute based on the sine of its index and elapsed time. Written in ES6 and ported from an older bl.ocks.org example, this SVG-based playground demonstrates how math functions can drive simple shapes into organic motion.