Make a single-file HTML page (everything inline, no dependencies or external assets) with a clean, dark hero scene. In the center, put a Red Hat–style fedora logo spinning smoothly in 3D. Keep it elegant — soft lighting, a sense of depth, nice shadows — with a small caption underneath. The layout should look good on any screen. When someone hovers or taps, slow the spin down and have the whole hat dissolve into thousands of tiny glowing particles that drift apart like embers, swirl around for a moment, then flow back together and reform the hat perfectly. A few of those particles should keep orbiting afterward, trailing faint light. Keep the glow tasteful. And respect reduced motion. Return only the finished HTML file.

Fedora Showdown gives every major AI model the same creative prompt and lets you compare the results side by side. The prompt asks each model to build a single-file HTML page with a spinning 3D Red Hat fedora that dissolves into particles on hover.

Harness / coding tool used per provider:
Anthropic models — Claude Code
OpenAI models — Codex (except GPT-5.5 Pro, which is not available in Codex and was done via the ChatGPT web interface)
Composer models — Cursor
All other models — Pi + OpenRouter

All models were run at the default effort level for their respective harness and model, unless otherwise noted. No cherry-picking, no retries, no manual edits. What you see is what each model produced on its first attempt.

Entries marked Ultracode were run using Claude Code's multi-agent mode (parallel implementations → judge → best result). This applies even when the model isn't from Anthropic — Claude Code supports overriding the Anthropic base URL to OpenRouter, so it orchestrates the workflow while the underlying model can be swapped to any provider.