✓ 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
All 21 features implemented in a single SVG-based file with correct Archimedes physics (1000 g, 51.8 cm³ pure gold vs 76.9 cm³ gilded), but the slider is custom-draggable SVG (not a native input) and the Heureka pulse uses a fragile font-size trick with a broken SVG transform-origin that may not render correctly cross-browser.
11,416 output tokens · claude-opus-4-6 · end_turn
All 21 features implemented in a single SVG-based file with correct Archimedes physics (1000 g, 51.8 cm³ pure gold vs 76.9 cm³ gilded), but the slider is custom-draggable SVG (not a native input) and the Heureka pulse uses a fragile font-size trick with a broken SVG transform-origin that may not render correctly cross-browser.