This example demonstrates animated circles that continuously move in a wave-like pattern across the screen, with the total number of circles oscillating over time. It shows how D3’s data join and enter/update/exit cycle handle dynamic datasets. The code uses `d3.select`, `d3.range`, and the `.join('circle')` method to bind an array of data points to SVG circle elements. Position and count update every frame using `setInterval` at 60 fps, with coordinates calculated from trigonometric functions. The SVG rendering scales to the full browser viewport.