✓ 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
All required features are implemented with correct physics (Au 19.3 g/cm³, gilded 4.5 g/cm³, same 1000 g mass), but the ASCII-canvas rendering draws crowns at the same computed position regardless of crown type, so the visual water-rise differential between them is approximate rather than per-crown, and the splash/heureka animations are functional but rudimentary.
All required features are implemented with correct physics (Au 19.3 g/cm³, gilded 4.5 g/cm³, same 1000 g mass), but the ASCII-canvas rendering draws crowns at the same computed position regardless of crown type, so the visual water-rise differential between them is approximate rather than per-crown, and the splash/heureka animations are functional but rudimentary.