✓ 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 = crowns in air is correct in label but the vertical slider's visual orientation is ambiguous with bt-lr writing-mode), crown animation is ASCII-art based with no true falling motion, and the particle splash logic shares a single particle array across two containers with flawed coordinate mapping, but physics values (mass 1000g, Au 19.3 g/cm³ → 51.8 cm³, alloy 13.0 g/cm³ → 76.9 cm³) and live readouts are correctly implemented.
Slider direction is inverted (value=0 at top = crowns in air is correct in label but the vertical slider's visual orientation is ambiguous with bt-lr writing-mode), crown animation is ASCII-art based with no true falling motion, and the particle splash logic shares a single particle array across two containers with flawed coordinate mapping, but physics values (mass 1000g, Au 19.3 g/cm³ → 51.8 cm³, alloy 13.0 g/cm³ → 76.9 cm³) and live readouts are correctly implemented.