Animated circles move vertically and pulse in size along a horizontal line, creating a wave-like rhythm. The visualization updates at 60 frames per second using a `setInterval` loop that increments a time variable. Each frame, the `prepData` function generates new positions and radii from sine functions, while the `vizData` function renders them as SVG circles via D3's data join. The code uses D3 v6 modules `select`, `range`, and the `.join()` pattern.