✓ 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 at top = air is correct, but writing-mode bt-lr means dragging up increases value → crown goes into water at top, which is backwards from expected UX); no true fall animation — crown teleports via ASCII reposition; splash is random noise per-frame with no temporal persistence.
Slider direction is inverted (value=0 at top = air is correct, but writing-mode bt-lr means dragging up increases value → crown goes into water at top, which is backwards from expected UX); no true fall animation — crown teleports via ASCII reposition; splash is random noise per-frame with no temporal persistence.