This live D3 example demonstrates the selection and merging of data-driven SVG circles, with positions adjusting over time based on sine waves. At each animation frame, the code uses D3's `select`, `range`, and the `join` selection API to reconcile the current dataset with rendered circles, updating their `cx` and `cy` attributes. The visualization shows smooth enter, update, and exit behavior as the number of circles varies with the sine function at 60 frames per second.