A green sine wave of circles moves continuously across the screen, with each circle’s vertical position and radius oscillating over time. The animation uses D3 v7’s `line` generator to draw a connecting path behind the circles, while `selectAll` and `join` update both the path and circle elements. Circles are generated fresh each frame via a custom `makeData` function, with rendering handled through SVG and a `setInterval` timer that adjusts the wave’s amplitude.