✓ Two crowns ✓ Same mass, different density ✓ Vertical slider ✓ Slider works ✓ Slider controls crowns ✓ Slider direction correct ✓ Full slider range — Fall animation ✓ Water displacement ✓ Rising water level ✓ Splash effects ✓ Physics correct ✓ Live mass value ✓ Live volume value ✓ Live density value ✓ Live displaced water ✓ Gilded displaces more ✓ Heureka animation ✓ No external deps ✓ Light bg / dark text ✓ Self-contained HTML
Solid, well-structured implementation with correct physics (1000g same mass, 19.3 vs 13.0 g/cm³, proportional displacement), working splash/heureka animations, and a clear dual-container layout — but no continuous fall animation (crowns teleport with slider rather than animate independently), and the underwater tinted-crown clipping technique is clever but the normal crown lacks explicit above-water clipping so it can visually overlap the water surface unrealistically.
Solid, well-structured implementation with correct physics (1000g same mass, 19.3 vs 13.0 g/cm³, proportional displacement), working splash/heureka animations, and a clear dual-container layout — but no continuous fall animation (crowns teleport with slider rather than animate independently), and the underwater tinted-crown clipping technique is clever but the normal crown lacks explicit above-water clipping so it can visually overlap the water surface unrealistically.