✓ 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
Fully-featured ASCII-art implementation hitting every required feature; main weakness is the character-grid rendering limits animation fidelity and the two tanks have independent water levels (which is physically correct for separate containers but obscures the classic side-by-side comparison narrative).
Fully-featured ASCII-art implementation hitting every required feature; main weakness is the character-grid rendering limits animation fidelity and the two tanks have independent water levels (which is physically correct for separate containers but obscures the classic side-by-side comparison narrative).