This example presents three animated circle charts, each with its own dataset and button. Clicking a button cycles through data values, causing the corresponding circle’s radius to transition smoothly while its numeric label updates. The visualization uses D3 v4 with `d3.select`, `d3.scaleLinear` for mapping data to radius and color, and `transition().attr` to animate changes. Each circle’s fill shifts along a gradient, and buttons trigger the updates through custom click handlers.