This example demonstrates a dynamic visualization of circles that move vertically in a sine-wave pattern, with the number of circles oscillating over time. Constructed with React and D3.js, the SVG rendering updates at 60 frames per second using an interval timer. The code leverages D3’s `select` to append an SVG canvas and `range` to generate data, while `selectAll` and `.join` bind circle elements to the evolving dataset. The animation adjusts each circle’s x and y coordinates based on a time variable, creating a fluid, rhythmic motion.