✓ 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 (tip labels say ⬆ Air / ⬇ Water, but slider min=0 maps to air and dragging down to max=100 moves crowns into water — the HTML orient/writing-mode vertical slider renders with top=0=air which is correct by convention, however the visual tip label is misleading and the -webkit vertical slider may render inverted on some browsers); physics values are solid (19.3 vs 5.1 g/cm³, same 1000g mass), ASCII art scene is feature-complete with splash, rising water, and a polished heureka overlay with flicker animation.
Slider direction is inverted (tip labels say ⬆ Air / ⬇ Water, but slider min=0 maps to air and dragging down to max=100 moves crowns into water — the HTML orient/writing-mode vertical slider renders with top=0=air which is correct by convention, however the visual tip label is misleading and the -webkit vertical slider may render inverted on some browsers); physics values are solid (19.3 vs 5.1 g/cm³, same 1000g mass), ASCII art scene is feature-complete with splash, rising water, and a polished heureka overlay with flicker animation.