Software engineering

AI & agentic development tooling

• claude-marketplace Plugin marketplace

  A personal Claude Code plugin marketplace — a catalog of plugins (skills, slash commands, agents, hooks) installable with one command.

• software-craft Claude Code plugin

  Slash commands for high-level software engineering: architecture, Domain-Driven Design, Architecture Decision Records, and quality & maintenance work.

• user-story-skills Claude Code plugin

  Skills and slash commands for user story refinement across the full lifecycle, from discovery through post-release — INVEST reviews, acceptance criteria, splitting, and more.

• polyptych-studio Python

  Turns a source essay into visual media — slide decks and single-page infographics — with multi-provider text and image generation.

• pixbridge Python · PyPI

  Multi-provider AI image generation library with a unified client API across Gemini, OpenAI, and xAI. Published on PyPI.

Static analysis: the arclens family

Structural analysis tools that extract a codebase's architecture, compute coupling metrics, detect cycles, and render reports and diagrams — one tool per ecosystem.

• arclens-kt Kotlin

  Static analysis for Kotlin codebases: dependency structure, coupling metrics, and architectural visualizations.

• arclens-java Kotlin

  The same analysis for Java programs, implemented in Kotlin.

• arclens-ts TypeScript

  Structural analysis for TypeScript and React codebases — afferent and efferent coupling, circular-dependency detection via Tarjan's SCC, Mermaid diagrams, and a self-contained HTML report.

Games & simulations

Browser-based, built with AI coding agents.

• space-v-simulator TypeScript

  A management simulation that teaches the verification paradox: higher AI adoption generates more code while review capacity stays fixed — without investing in verification, delivery slows down.

• vibe-crossword-tile-game TypeScript · React

  A Scrabble-like single-page game against an AI opponent with three difficulty levels — full rules, cross-word validation, bingo bonus.

• city-guessing-game TypeScript · React

  Guess-the-city quiz: a red dot on a continent map, multiple-choice answers. Built with React and Leaflet.

• flag-learning-game TypeScript

  A vibe-coded game for learning the flags of the world's countries.

• mazes-for-programmers TypeScript

  Maze generation and solving algorithms from Jamis Buck's "Mazes for Programmers", with a solver arena where pathfinding algorithms race through generated mazes.

Ray tracing & algorithms

• ray-tracer-challenge-rust Rust

  A Rust port of Jamis Buck's "The Ray Tracer Challenge", verified by the book's own Cucumber/Gherkin specs — 313 scenarios.

• ray-tracer-challenge Kotlin

  The same book implemented in Kotlin.

• from-the-ground-up-ray-tracer Kotlin

  A ray tracer inspired by Kevin Suffern's "Ray Tracing from the Ground Up".

• location-based-nearest-neighbours Scala

  Nearest-neighbour search with k-d trees on Apache Spark.

• GeomAlgLib Haskell

  A library of geometric algorithms and data structures for Haskell — convex hulls, triangulations, Voronoi diagrams — written in 1998 for my diploma thesis, and still building on a current GHC.

AI experiments

• ai-playground Python

  Examples for the OpenAI API and LangChain.

• ai-text2image Python

  Round-trip experiment: GPT describes an image, then an image model regenerates it from that description.

• gemini-cli-news JavaScript

  A small RSS reader for InfoQ news, built to try out Google's gemini-cli.

Article & talk code

• jdk24_structured_concurrency Java

  Example code for my JavaSpektrum article on Structured Concurrency — the JDK 24, 25, and 26 preview APIs kept side by side so the differences are easy to see.

• codingdavinci-familiennamen TypeScript

  Documents and code from the "Coding da Vinci Nord" 2016 culture hackathon, analyzing a family-names dataset.

The archive

Older talk and article code, kept read-only: Kotlin coroutines (parallel 2019) · structured concurrency warm-up (KKON 2021) · KKON 2022 talk · cuDNN example from iX Developer 2018 · GPU computing (parallel 2017) · parallel 2015 · parallel 2014 · parallel 2012 · email analysis with Spring Boot & Elasticsearch · disk-usage pie charts in Groovy · Eclipse Modeling Framework with Groovy · Common Warehouse Metamodel in EMF · family-name graphs via Levenshtein distance · Markov chains for Ruby Quiz 74 (2006).