✓ 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 strong visual polish; the only physics concern is that the water-rise pixel scaling uses an ad-hoc RISE_SCALE constant (0.45 px/cm³) rather than a geometrically derived tank cross-section, making the rise values loosely calibrated but directionally correct.
13,153 output tokens · claude-opus-4-6 · end_turn
All required features are implemented with strong visual polish; the only physics concern is that the water-rise pixel scaling uses an ad-hoc RISE_SCALE constant (0.45 px/cm³) rather than a geometrically derived tank cross-section, making the rise values loosely calibrated but directionally correct.