✓ 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
Comprehensive ASCII-art implementation hits every required feature including correct physics (Au ρ=19.3, fake ρ=8.5, same 1000g mass), live panel values, rising water, splash, and a multi-frame Heureka overlay, but both crowns share a single subFrac so they move/submerge identically, losing any visual differentiation in displacement rate.
Comprehensive ASCII-art implementation hits every required feature including correct physics (Au ρ=19.3, fake ρ=8.5, same 1000g mass), live panel values, rising water, splash, and a multi-frame Heureka overlay, but both crowns share a single subFrac so they move/submerge identically, losing any visual differentiation in displacement rate.