This example shows a field of animated circles whose positions and radii oscillate sinusoidally, creating a flowing wave-like pattern across the screen. Using D3 v7 with the `select` and `range` modules, the code generates a dataset via `makeData` and updates the SVG through a selection join on `<circle>` elements. A `setInterval` drives a 60-frames-per-second loop, incrementing a time variable that modifies each circle’s `cx`, `cy`, and `r` attributes, producing seamless, continuous motion.