A dynamic swarm of circles fills the screen, with each circle's position and size oscillating smoothly over time based on a sine wave. The visualization demonstrates D3's data join pattern using `selectAll`, `data`, and `join` to efficiently update the SVG elements every millisecond. Built with React, it uses D3's `range` and custom `makeData` and `vizData` functions to generate coordinates and radii from the current time step. The animation runs continuously via `setInterval`, rendering synchronized, wave-like patterns across the viewport.