✓ 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 physics demo with correct Archimedes values and live data panel, but slider direction is inverted (slider bottom = air, top = water per the rtl/vertical-lr CSS trick making value=0 render at top visually but map to "out of water", yet the label says ▲ top means above water and ▼ bottom means submerged — however the writing-mode+direction combo means dragging down increases value which correctly increases immersion, so direction is actually correct), no smooth fall animation (crown teleports), and splash is ASCII-character-only with no CSS animation frames.
Solid ASCII-art physics demo with correct Archimedes values and live data panel, but slider direction is inverted (slider bottom = air, top = water per the rtl/vertical-lr CSS trick making value=0 render at top visually but map to "out of water", yet the label says ▲ top means above water and ▼ bottom means submerged — however the writing-mode+direction combo means dragging down increases value which correctly increases immersion, so direction is actually correct), no smooth fall animation (crown teleports), and splash is ASCII-character-only with no CSS animation frames.