The 33Day-Diary

A structured journal that leads through a sort of meditation routine for 33 days, based on positive psychology. A page with more infos is available in english at and in german at

I needed something like the five minute journal for myself, but I was inspired to integrate some extensions into that idea and wanted it to be a beautiful physical object…

Now, the 3rd revision is done. A collaborator of mine handcrafts the books and gives every copy a unique design. I did a photo shoot of a bunch of example copies and had it professionally translated.


Mellowtree is my indie music project. Dreamy, spacey, catchy art pop. I’ve been following this vision since I was 14, and created countless ideas.

Currently I’m focusing on generating more viable output, i.e. I’m working on a 10 track debut album. Collaborators are welcome, in particular instrumentalists.

Flowtoolz Studio

Since around 1996, I’ve been growing (gardening?) a music home studio, and I’m pretty happy with the minimal but effective and high quality setup.

Since I’m drifting more and more to the production side, I collaborate with musicians and produce their demos. A page with details will follow…


A real minimal but viable and fun macOS app for taking notes and managing tasks. Check out There’s much more to come for this project…

I created Flowlist for myself out of frustration with all the task management apps I intensely used before. Now I’m happy using Flowlist daily since summer 2017.

Flowtoolz Github

I just started to put some code on Github. Most notably, I released SwiftObserver, a framework for reactive Swift programming, which you can install via Cocoapods and via Carthage.

You’ll also find UIObserver (a UI layer for SwiftObserver) and the general helper frameworks SwiftyToolz, FoundationToolz and UIToolz, only UIToolz is not yet available via Carthage or Cocoapods.

Zen in the Art of Software Architecture

… is the tongue-in-cheek working title of a book I’m writing. It will be a casual and entertaining but also consistent and systematic dive into the fundamental principles that make software hold together or fall apart.

I’ve been obsessing about the nature of software structure since I started coding at age 12. Now I’m gathering and integrating all my notes and writings on the subject. The draft is currently 80+ pages long.

The book is not exclusively directed at coders, but at everyone in the periphery of software development. It will have no code in it, not even pseudo code! It offers a fundamental and new perspective on the qualitative aspects of software, and it will contain lots of hand-drawn diagrams.

As soon as the overall “story arc” is settled, I’ll extract some parts as blog posts…


An idea for a code visualization and quality analytics tool around iOS, macOS and tvOS. Although there’s no finished app to show, I’ve done a lot of conceptual work, copywriting, market analysis and so forth. And I explored the idea through the London Real Business Accelerator.

Watch the pitch here, or if you’re interested in collaborating on such a project, download some conceptual notes here. More is to come at


In 2017, I got into trading stocks, in particular swing trading via chart technique. I built an app that visualizes historic stock data from an unofficial API of yahoo finance.

The app also allowed me to test simple strategies and see how they compete. Supported by this app, I made money with every single trade, but I wasn’t too systematic about it. I’ll certainly come back to this project in the future.


A simple but highly effective app for expanding your vocabulary in your own or in a foreign language. It trains your recall of the most used terms that you recently didn’t know. The prototype worked well.

I hope I can pick this up at some point. If you’re interested in collaborating on such a project, download a german summary of this vision here.

Human-Audio Interaction Lab

During my master studies in Information Engineering, I became obsessed with a vision of a novel music composition interface. So I made it the subject of my thesis.

While I still stand behind the 36 requirements for music composition interfaces, my solution suffered from overthinking, and the academic prototype is not a minimal viable product. I don’t know that I will ever come back to this, since other ideas have more commercial potential.

Academic Writings

Listing all Maximal Cliques of Large Sparse Graphs

Direct Manipulation

GPU Based Stochastic Foliage Simplification

Die Erkenntnisleistung der Literatur

Deriving Semantic Word Distances from Web Search Hits

Visualization of Subspace Clusterings for High Dimensional Data

What Music Composition Interfaces Require

HAIL: Developing the Human-Audio Interaction Lab

Interaction Design for Mobile Music Composition

Idea for a metric distance function (“semantic diameter”) on n feature vectors, rooted in information theory