✓ 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
ASCII-art rendering is functional and physics values are correct (gold 19.3 g/cm³, alloy 13.0 g/cm³, same 1000 g mass), but the crown is drawn as a single Unicode character with minimal submersion detail, the splash effect is trivial static asterisks, and there is no true fall animation — the crown teleports rather than animates between positions.
ASCII-art rendering is functional and physics values are correct (gold 19.3 g/cm³, alloy 13.0 g/cm³, same 1000 g mass), but the crown is drawn as a single Unicode character with minimal submersion detail, the splash effect is trivial static asterisks, and there is no true fall animation — the crown teleports rather than animates between positions.