✓ 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 prompt requirements are met with correct physics (19300/11300 kg/m³, same 1000g mass), live data panels, differential water rise, splash particles, and a full Heureka overlay — minor UX weakness is the custom SVG drag-slider instead of a native range input, which can feel imprecise and has a coordinate-mapping quirk (localY subtracts only the group's translate Y, not accounting for the outer SVG offset reliably across viewport sizes).
12,824 output tokens · claude-opus-4-6 · end_turn
All prompt requirements are met with correct physics (19300/11300 kg/m³, same 1000g mass), live data panels, differential water rise, splash particles, and a full Heureka overlay — minor UX weakness is the custom SVG drag-slider instead of a native range input, which can feel imprecise and has a coordinate-mapping quirk (localY subtracts only the group's translate Y, not accounting for the outer SVG offset reliably across viewport sizes).