A growing sine wave is drawn as a black line across the screen, with large, colorful circles positioned along it whose radii expand and whose fill colors cycle through a seven-color palette. The animation updates sixty times per second, shifting the wave’s phase and recalculating circle positions. Built with D3 v7, the example uses `d3.select`, `d3.range`, and a `line` generator, applying data joins and `transition` methods to animate circle attributes. It demonstrates the reuse of a data-bound selection function across two stacked SVG layers.