— 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
Completely misses the prompt's core requirements (two crowns, vertical slider controlling submersion, fall/splash animations, Heureka moment); instead implements a generic Archimedes buoyancy demo with shape/density sliders and correct physics calculations but zero crown-specific narrative.