Tree Appreciator
- ID
- 35616
- Status
- summarized
- Published
- 15 Oct 2026, 5:23 AM
- Fetched
- 15 Oct 2026, 9:22 PM
- Provider
- Simon Willison
- Category
- developer-ai
- Original URL
- https://simonwillison.net/2026/Oct/14/tree-appreciator/
- Source URL
- https://simonwillison.net/atom/everything/
Summary
- Score
- 6.5
- Created
- 15 Oct 2026, 9:22 PM
- Tags
- Audience
- vibe_codersai_agent_usersdevelopersai_ml_learners
What happened
Simon Willison created "Tree Appreciator," a Three.js spot-the-difference game about two algorithmically generated trees, using the default Claude iPhone app in chat mode with Claude Opus 5.5 Max. The prompt included instructions to "Think hard" and "make sure it is both fun and beautiful"; Claude took 3 hours and 7 minutes to return a game with music, animation, and achievements. Willison notes that telling Opus 5.5 "make sure it is fun" worked "uncomfortably well," and that this was chat mode, not Claude Code mode.
Why it matters
If you vibe-code generative UI or games, this is a concrete datapoint: a single chat-mode Claude Opus 5.5 Max prompt ran for 3h7m and produced a polished Three.js game. Try the explicit "make sure it is fun" clause on your next generative game/UI prompt, and decide whether you still need Claude Code for this kind of task or whether long chat-mode runs are enough.
Discussion angle
What does the 3h7m chat-mode run say about long single prompts versus agentic coding tools, and which prompt clauses like "think hard" or "make sure it is fun" actually improve generative game/UI output?