20 things I built and am actually happy with. More sit on GitHub.
A ladder-logic puzzle game: program a Mitsubishi-style PLC to solve motor-control problems, then get graded by an engine that runs identically on client and server.
Daily language practice on the web and Android that adapts to what you keep getting wrong, with stories, streaks and an honest progress model.
A physics puzzle game about building bridges on a budget. Every beam carries real load, and the stress graph shows exactly which part gave way.
Skriv din dataåtkomst en gång. Börja med SQLite och byt till Postgres, MySQL eller MariaDB genom att ändra en rad. En gemensam testsvit bevisar att alla adaptrar beter sig likadant.
En jobbsökartjänst som körs lokalt och är byggd kring en enda fråga: har jag redan sökt här? Dubblettkontroll, sökning på betydelse, ett webbläsartillägg och en MCP-server för AI-assistenter.
A scientific calculator for Android modeled on how the TI-83 Plus home screen works, with its own look. It has a dot-matrix LCD, sculpted keys, variables, `Ans`, and a memory of recent calculations. Graphing and programming are deliberately left out. Built with Kotlin and Jetpack Compose. There are no third-party runtime dependencies beyond AndroidX.
A scientific calculator with the feel of a classic graphing calculator's home screen: a dot-matrix LCD, sculpted keys and the keystrokes you already know.
Sunrise, sunset, twilight, golden hour and the moon for any day and any place, plus network-synced atomic time on a watch dial. Calculated on the phone, with no account and no tracking.
A puzzle game where every wave is real: the board is a live simulation of the wave equation, so walls reflect, lenses focus and two sounds cancel because the physics says so.
Send one message to up to four models at once and watch the replies stream side by side, each pane with its own model, system prompt and settings.
A disk reclamation tool for Windows. It finds space you can actually get back, tells you what removing it will cost you, and keeps a record of everything it removed.
An autonomous agent with persistent memory, run outside any chat UI, with a console to approve or reject what it wants to do next.
A WebAuthn / FIDO2 passkey demo built around a hardware security key, with TOTP and recovery-code fallbacks and a live ceremony debug panel.
Hohmann transfers, gravity assists and the Oberth effect you can fly in 3D, with real Kepler physics under every animation and replays of eight historic missions.
A physically based rotating black hole, ray-traced in the browser: null geodesics integrated through the Kerr metric in a WebGPU compute shader.
A VS Code extension that checks MCP server source as you write it: missing tool descriptions, malformed input schemas, duplicate names and bloated descriptions.
Open, edit and create Word documents, and read Excel workbooks, entirely in the browser. Files are parsed client-side and never leave your machine.
A Markdown editor and viewer for the browser: several documents open at once, a live split-pane preview, and everything saved locally.
Speech transcription that runs Whisper on your GPU inside the browser tab. No server and no API key.
A SimCity 4-style isometric city builder in the browser, with zoning, power and water networks, traffic, pollution, land value and an annual budget.