✓ 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
Buoyancy formula is double-applied (multiplied by G twice: `rho * V * G * 9.81`) giving wrong force values; slider direction is inverted (value=0 at top = air is correct per HTML but the vertical slider's `direction: rtl` + `writing-mode: vertical-lr` behavior on most browsers actually maps slider bottom to higher values, making top=water); no smooth fall animation — crowns teleport via slider mapping without any time-based drop sequence.
Buoyancy formula is double-applied (multiplied by G twice: `rho * V * G * 9.81`) giving wrong force values; slider direction is inverted (value=0 at top = air is correct per HTML but the vertical slider's `direction: rtl` + `writing-mode: vertical-lr` behavior on most browsers actually maps slider bottom to higher values, making top=water); no smooth fall animation — crowns teleport via slider mapping without any time-based drop sequence.