✓ 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
Both crowns descend identically at all slider positions so the gilded crown never visually displaces more water, the slider direction is inverted (0%=air top is correct but the vertical slider renders with bottom=high value meaning bottom=water which is correct — however the slider uses writing-mode bt-lr making the visual top map to value 0/air which is actually correct, but the gold density label is "SILVER" and physics for displaced water calculation is poorly heuristic rather than Archimedes-correct), and the ASCII-art rendering is functional but visually rudimentary.
Both crowns descend identically at all slider positions so the gilded crown never visually displaces more water, the slider direction is inverted (0%=air top is correct but the vertical slider renders with bottom=high value meaning bottom=water which is correct — however the slider uses writing-mode bt-lr making the visual top map to value 0/air which is actually correct, but the gold density label is "SILVER" and physics for displaced water calculation is poorly heuristic rather than Archimedes-correct), and the ASCII-art rendering is functional but visually rudimentary.