Zetris is a classic falling-blocks puzzle game, created as the first experiment to test the coding capabilities of Claude Sonnet 4, Anthropic’s AI. A project born from curiosity to explore how far artificial intelligence can go in creating functional and enjoyable games. The game is completely free, all the code is viewable directly on the web page, and you can also install it as an app to play offline. Try it now and discover what an AI can create with the right instructions!