# Tree Appreciator

> Source: <https://simonwillison.net/2026/Oct/14/tree-appreciator/>
> Published: 2026-10-14 21:23:01+00:00

**Tool:** [Tree Appreciator](https://tools.simonwillison.net/tree-appreciator)

Another game experiment with Claude. This one used the default Claude iPhone app (chat mode, not Claude Code mode), where I prompted Claude Opus 5.5 Max with:

`Build a three js game called "Tree appreciator" - it shows you two algorithmically generated trees and the game mechanics is about appreciating the differences between them. Think hard about how to make sure it is both fun and beautiful.`

Somewhat embarrassingly given [my recent talk](https://simonwillison.net/2026/Sep/27/2026-in-llms-so-far/#simon-willison-2026-in-llms.059.webp), I've found that telling Opus 5.5 "make sure it is fun" works uncomfortably well. In this case Claude [crunched for 3 hours and 7 minutes](https://claude.ai/share/ee7de555-f85c-4ff0-96cb-d51ed5e479e9) before retuning a cosy little spot-the-difference game with music and animation and achievements that's quite compelling to play.

Tags: [game-design](https://simonwillison.net/tags/game-design), [javascript](https://simonwillison.net/tags/javascript), [ai](https://simonwillison.net/tags/ai), [generative-ai](https://simonwillison.net/tags/generative-ai), [llms](https://simonwillison.net/tags/llms), [claude](https://simonwillison.net/tags/claude), [vibe-coding](https://simonwillison.net/tags/vibe-coding), [three-js](https://simonwillison.net/tags/three-js)