✓ 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 maps to crowns in air, which is technically correct by convention, but the vertical CSS uses writing-mode+direction that reverses the physical drag so top of the track visually = 100 = submerged, making UX feel backwards); physics values are accurate (19.3/8.5 g/cm³, correct displaced volumes), and the ASCII grid scene with splashes, rising water, heureka cycling frames, and live info panel is impressively complete, but the ASCII crown rendering is rudimentary and the water fill pattern overwrites submerged crown characters.
Slider direction is inverted (value=0 at top maps to crowns in air, which is technically correct by convention, but the vertical CSS uses writing-mode+direction that reverses the physical drag so top of the track visually = 100 = submerged, making UX feel backwards); physics values are accurate (19.3/8.5 g/cm³, correct displaced volumes), and the ASCII grid scene with splashes, rising water, heureka cycling frames, and live info panel is impressively complete, but the ASCII crown rendering is rudimentary and the water fill pattern overwrites submerged crown characters.