✓ 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 maps to crowns in air, but the slider's vertical orientation with `bt-lr` writing mode means visually dragging up increases value, so bottom=air/top=water); mass/volume/density values are static labels not live-updating; no fall animation (crowns teleport); displaced water correctly differs between crowns but water-level rise scaling is visually unconvincing.
Slider direction is inverted (value=0 at top maps to crowns in air, but the slider's vertical orientation with `bt-lr` writing mode means visually dragging up increases value, so bottom=air/top=water); mass/volume/density values are static labels not live-updating; no fall animation (crowns teleport); displaced water correctly differs between crowns but water-level rise scaling is visually unconvincing.