Show HN: I built a game on my old phone without knowing what I was building

Summary

The Starting Point “Create a web-based game that leverages the accelerometer creatively.” That was the entire spec. No wireframes, no design doc, no feature list. I typed this into Claude Code running on my Redmi Note 9 - a 4-year-old Android phone with 4GB RAM. Three hours later, I had Inertia - a WebGL marble game with procedural terrain and dynamic camera. The interesting part isn’t the game itself. It’s that I didn’t know I was building a marble game until iteration 4. Inertia gameplay showing the ring-sphere player navigating 3D terrain This Isn’t Vibe Coding “Vibe coding” typically means: you know what you want to build, you just let AI handle the implementation details. You have a mental image of the end product - maybe a todo app, a chat interface, a dashboard - and you describe it loosely while the AI figures out the code. What I’m describing is different. I’ll call it Vibe Discovery: you don’t know what you’re building. The requirements themselves are undefined. You’re not just discovering implementation - you’re discovering what the product should be. The distinction matters: “Build me a todo app with drag-and-drop” “Build me something fun with the accelerometer” Requirements known, implementation fuzzy Requirements unknown, discovered through building AI translates intent to code AI proposes, human reacts, product emerges End state imagined upfront End state discovered through iteration In Vibe Discovery, you’re not directing - you’re reacting. Each prototype teaches you what you actually want. The Setup Termux running Claude Code on a phone screen The whole thing ran on a Redmi Note 9 - a 5-year-old basic Android phone with 4GB RAM. Termux for the terminal, Claude Code for the AI, Node.js http-server for testing, GitHub for deployment. The entire feedback loop - build, test, react, iterate - happened in seconds on a single device. That speed is what makes Vibe Discovery work. Why the Phone? You might ask: “Why not just do this on a laptop?” Sensor Loop:...