✓ 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 maps to crowns in air, but the vertical slider's writing-mode+direction RTL means the physical top corresponds to value=100/water, bottom=0/air); no smooth fall animation — crown teleports frame-to-frame via slider position only.
Slider direction is inverted (value=0 maps to crowns in air, but the vertical slider's writing-mode+direction RTL means the physical top corresponds to value=100/water, bottom=0/air); no smooth fall animation — crown teleports frame-to-frame via slider position only.