✓ 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
ASCII-art rendering is functional and physics values are correct (gold 19.3 g/cm³, fake 13.0 g/cm³, same mass), but slider direction is inverted (value=0 at top means crowns in air only by convention with `writing-mode: bt-lr`, crown movement logic maps depth=0 to top and depth=100 to bottom which is correct, but the visual slider handle starts at top=0%=air which is acceptable — however the crown "fall" is computed, not animated — no splash effects, no smooth frame animation, and the random `~` water causes flickering on each call rather than smooth animation.
ASCII-art rendering is functional and physics values are correct (gold 19.3 g/cm³, fake 13.0 g/cm³, same mass), but slider direction is inverted (value=0 at top means crowns in air only by convention with `writing-mode: bt-lr`, crown movement logic maps depth=0 to top and depth=100 to bottom which is correct, but the visual slider handle starts at top=0%=air which is acceptable — however the crown "fall" is computed, not animated — no splash effects, no smooth frame animation, and the random `~` water causes flickering on each call rather than smooth animation.