Tree Appreciator
A calm spot-the-difference game played on two procedurally grown 3D trees.
Official site tools.simonwillison.net, verified Nov 3, 2026. Linked from the developer's own post on simonwillison.net.
Where to play
Every platform this game is on. Links are checked against official sources; we never host or mirror games.
- Play free — official siteBrowserReleasedFree
Runs in a desktop or mobile browser. No download.
Browser (no download) · Desktop · Mobile · Official link verified Nov 3, 2026.
About Tree Appreciator
Tree Appreciator is a slow spot-the-difference game. Each round grows two 3D trees from one seed, and the player finds the three small things that differ. Finished pairs are collected in a herbarium, and every third pair is followed by a Connoisseur's round. Simon Willison says he made it in the regular Claude chat interface from one prompt, with no follow-up prompting. His tools colophon credits Claude Opus 5.5 Max. It is free to play in the browser.
How it was built
VerifiedBuilt in the regular Claude chat app (claude.ai), not Claude Code, from a single prompt asking for a three.js game called Tree appreciator that shows two algorithmically generated trees and is about appreciating the differences between them. The developer says no iteration or follow-up prompting was needed. The tools colophon credits commit dafb677 (14 Oct 2026) to Claude Opus 5.5 Max and links the shared transcript.
One-shot prompt in the Claude chat app. The result is one static HTML page that uses three.js / WebGL, and it makes no AI calls at runtime. Progress is saved in the browser.
- Engine / framework
- three.js
- Languages
- JavaScript, HTML
- Team size
- Not disclosed
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“This game required no iteration or follow-up prompting at all—I got the game in a single shot.”Verification notes: We checked the tool, the one-shot claim and the play link in the developer's post. The model, commit and date come from the tools colophon. We read the features from the game page. The post does not name the model, and the game page does not mention AI.
Development history
Published on tools.simonwillison.net (commit dafb677, credited to Claude Opus 5.5 Max).
Developertools.simonwillison.netDescribed in the developer's post on vibe game development as built in a single shot in the Claude chat app.
Developersimonwillison.net
Game performance
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Not publicly available: Concurrent players (site), Monthly revenue, Gross revenue.
Sales & revenue (all platforms)
Browser game — there are no downloads to count.
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Sources
| Source | Type | Published | Accessed |
|---|---|---|---|
| The October inflection point for vibe game development simonwillison.net | Devlog | Oct 28, 2026 | Nov 3, 2026 |
| tools.simonwillison.net colophon (tree-appreciator) tools.simonwillison.net | Official site | Not confirmed | Nov 3, 2026 |
| Tree Appreciator (game page) tools.simonwillison.net | Official site | Not confirmed | Nov 3, 2026 |
| Official game page (language check) Simon Willison | Official site | Not confirmed | Nov 3, 2026 |
