✓ 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
Slider direction is inverted (value=0 at top puts crowns in air correctly but the slider thumb starts at top=0 which is labeled as crowns in air — actually direction may be correct, but the water rendering has a critical bug: water level uses waterRise which starts near-zero and never shows a meaningful base water level, so tanks appear empty until submerged; also no smooth fall animation — crown teleports based on slider with no time-based animation.
Slider direction is inverted (value=0 at top puts crowns in air correctly but the slider thumb starts at top=0 which is labeled as crowns in air — actually direction may be correct, but the water rendering has a critical bug: water level uses waterRise which starts near-zero and never shows a meaningful base water level, so tanks appear empty until submerged; also no smooth fall animation — crown teleports based on slider with no time-based animation.