Fifteen circles orbit around the center of the screen, their radii pulsing as they move along a tangent path. The visualization demonstrates d3 data joins using `selectAll`, `data`, and the `join` method to bind an array of objects to SVG circle elements. Each animation frame generates new data with `d3.range` and updates the circles' `cx`, `cy`, and `r` attributes inside a `setInterval` loop. The example uses d3 v6 with SVG rendering and continuous animation.