AI Inspiration WorldWhat it is
Tree Appreciator is a browser game Simon Willison released on October 14. Each round grows two 3D trees from the same seed, with a few small differences between them: a missing bough, a visiting bird, a branch that turned early. Tap a difference to mark it as noticed. Hints are limited, and you can drag and zoom to see the trees from any angle. Finish a pair to earn appreciation points, leaves and new entries in your herbarium; there's music, animation and achievements too. On his blog, Willison says he used the regular chat mode of the Claude iPhone app with Claude Opus 5.5 Max, and his prompt included "Think hard about how to make sure it is both fun and beautiful." Claude worked on it for 3 hours and 7 minutes. The pace is the point: spot-the-difference slows down into a few minutes of really looking at trees.
Who it's for: anyone who likes quiet little games and wants a few minutes of slow looking, and anyone curious what AI can build from a plain chat on a phone.
Before you start: open it in a browser with no install or sign-in; it lives on the author's own site. It works with touch on phones and on computers, where keyboard controls are listed too. The 3D view runs on WebGL and may be slow on older devices; we haven't tested it. We read the source at a fixed version: the page doesn't use the camera, microphone or location, your progress is saved in this device's browser, and we found no code that uploads it. The page loads Google Fonts and the three.js graphics library from the web, so it isn't fully offline. The interface is in English, with no age rating given. It's free, and the source is in the simonw/tools repository under the Apache-2.0 license.
Based on the game page, its source code and the author's blog. Not tested by AI Inspiration World.