✓ 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
Solid ASCII-art implementation with correct physics (gold 19.3 g/cm³, fake 8.9 g/cm³, same mass), live info panel, splash effects, and Heureka overlay, but the slider direction is inverted (value=0 top = crowns in air is correct mechanically, yet CSS `direction:rtl` on a vertical slider makes the physical top of the thumb correspond to max, so user dragging up submerges crowns rather than raising them), and there is no smooth fall animation — crowns jump position linearly with no drop/gravity feel.
Solid ASCII-art implementation with correct physics (gold 19.3 g/cm³, fake 8.9 g/cm³, same mass), live info panel, splash effects, and Heureka overlay, but the slider direction is inverted (value=0 top = crowns in air is correct mechanically, yet CSS `direction:rtl` on a vertical slider makes the physical top of the thumb correspond to max, so user dragging up submerges crowns rather than raising them), and there is no smooth fall animation — crowns jump position linearly with no drop/gravity feel.