This example demonstrates D3 selection and data-join patterns by animating a series of circles and connecting lines across a full-screen SVG. As time progresses, the circles oscillate vertically along sine waves while lines link consecutive points. The code uses `d3.select`, `d3.range`, and the `selection.join` method to bind and update elements each frame. Rendering is driven by a `setInterval` loop that regenerates the data and re-applies the `makeCircle` and `makeLine` functions, highlighting how D3 manages enter, update, and exit states.