{"version":"1.0","type":"rich","title":"enter update exit","description":"Fifteen circles undulate in a continuous, animated sine-wave pattern across the screen, their vertical positions and radii oscillating as time advances. The code uses D3's `selectAll`, `data`, and `join` to manage enter, update, and exit states for each circle, while a `setInterval` loop updates the dataset every 50 milliseconds. All rendering is done via SVG elements appended to the body, with dynamic attributes for `cx`, `cy`, and `r` computed from trigonometric functions. The example demonstrates a simple, non-interactive harmonic motion visualization driven entirely by D3's data join and timed updates.","provider_name":"VizHub AI Studio","provider_url":"https://vizhub.com","html":"<iframe src=\"https://vizhub.com/viz/cecffbfdd42148fa800048152d167a91?mode=embed\" width=\"960\" height=\"500\" scrolling=\"no\" frameborder=\"0\"></iframe>","width":960,"height":500,"cache_age":3600}