✓ 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
Exceptionally complete SVG-based demo with correct physics (1000 g / 19.3 vs 13.0 g/cm³, volumes 51.8 vs 76.9 cm³), animated splashes, wave effects, live data panels, and a Heureka animation — only weaknesses are the custom drag-only slider (no native range input, so scrubbing feel is limited) and mass/density values are static text rather than truly dynamic readouts.
10,873 output tokens · claude-opus-4-6 · end_turn
Exceptionally complete SVG-based demo with correct physics (1000 g / 19.3 vs 13.0 g/cm³, volumes 51.8 vs 76.9 cm³), animated splashes, wave effects, live data panels, and a Heureka animation — only weaknesses are the custom drag-only slider (no native range input, so scrubbing feel is limited) and mass/density values are static text rather than truly dynamic readouts.