✓ 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 means crowns start in air correctly, but the CSS writing-mode+rotate trick means dragging down visually increases depth, which may confuse direction semantics); ASCII art lacks smooth fall animation — crown just teleports position proportionally with no inertia or distinct entry frame; splash particles exist but are rarely visible due to timing logic; physics values (gold 19.3, alloy 13.0 g/cm³, same 1000g mass) are accurate and the water-rise difference between crowns is correctly rendered.
Slider direction is inverted (value=0 at top means crowns start in air correctly, but the CSS writing-mode+rotate trick means dragging down visually increases depth, which may confuse direction semantics); ASCII art lacks smooth fall animation — crown just teleports position proportionally with no inertia or distinct entry frame; splash particles exist but are rarely visible due to timing logic; physics values (gold 19.3, alloy 13.0 g/cm³, same 1000g mass) are accurate and the water-rise difference between crowns is correctly rendered.