circle dance end
Two buttons trigger the same animated update for a small set of circles, moving each circle’s center and radius to new values over two seconds. The visualization shows three red circles on an SVG canvas, with the animation smoothly interpolating their positions and sizes via D3’s `.transition()` and `.attr()` methods. The data consists of hardcoded JavaScript arrays of `x`, `y`, and `r` values, and the code uses D3 v4’s selection `.enter()`, `.merge()`, and `.transition().duration()` to handle the state change.