Two circles bounce between expanding and contracting in a loop, with one radius derived from a random integer and the other responding inversely to it. Built with D3 v6, the animation uses `setInterval` to regenerate data and update SVG circle attributes `r`, `cx`, and `cy` every 100 milliseconds. The `ball2radiusMaker` function toggles the second circle’s size based on whether the random value exceeds the midpoint, creating a visual counterpoint. The code reads as an algorithmic sketch inspired by Sol LeWitt’s geometric rules.