✓ 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
Slider direction is inverted (value=0/top = crowns in air is correct conceptually but the slider thumb at top maps to t=0 which is correct — however the vertical slider with direction:rtl and writing-mode renders with bottom=high value, so physically moving the thumb down increases immersion, which is inverted UX); no smooth fall animation (crown position jumps discretely via slider only, no autonomous animation); ASCII art rendering is competent with water ripple and splash chars, but the requestAnimationFrame loop re-renders every frame even without slider change causing unnecessary CPU use and flickering splash noise.
Slider direction is inverted (value=0/top = crowns in air is correct conceptually but the slider thumb at top maps to t=0 which is correct — however the vertical slider with direction:rtl and writing-mode renders with bottom=high value, so physically moving the thumb down increases immersion, which is inverted UX); no smooth fall animation (crown position jumps discretely via slider only, no autonomous animation); ASCII art rendering is competent with water ripple and splash chars, but the requestAnimationFrame loop re-renders every frame even without slider change causing unnecessary CPU use and flickering splash noise.