This example demonstrates a dynamic data-join animation using D3 v7, where fifteen circles move horizontally in a sine-wave pattern that updates every second. The visualization uses `setInterval` to increment a time variable, generating new x and y coordinates for each circle based on its index and the sine of its position plus time. The code employs D3's `selectAll().data()` join method to enter and update SVG circle elements, animating their `cx` and `cy` attributes smoothly as the wave oscillates vertically. The SVG rendering adapts to the full browser window dimensions.