Jujutsu VCS - short introduction

Jujutsu (jj) is a VCS unlike most other, its user interface is separated from it storage system(s). This allows it to serve as a VCS with many possible physical backends, that may have different data/networking models.

Currently it uses git by default as storage layer, making it compatible with all the existing git ecosystem.

Martin started it as a hobby project in 2019, and now it’s his full-time project at Google.

Garmin RepaField

A few weeks ago there was a rainy weekend and I was not able to do the planned work in the garden, also the Vadlan Ultra Terep trail running competition was near, so I decided to create my own Garmin watch datafield.

My main plan was to display both the stamina and the remaining distance from the track in a comparible way (among other metrics I’m interested in, like heart rate, pace and such), but that failed since many metrics are not available through the SDK - stamina among them. But anyway, I’ve created my datafield, I really like it, and at the moment of writing 178 other runners have installed it, too.

You can download it from the Garmin Connect IQ store.


I’m planning to create a custom web component which lets you easily embed your fragment shaders into any website for a long time. You can find some (mostly abandoned ones) on github, so this is my take on the topic (to abandon it eventually 😉).

It tries to be compatible with https://twigl.app/, supporting geekest mode and MRT as well (but only 300 es).

See details on github.

WebGL Planet

Sometimes I have the itch to create something that’s not (just) useful, but pleases the eyes.

I’ve started experimenting with webgl a few years ago, mostly in shadertoy - but most of my experiments aren’t public.

This (fullscreen) is one of my favourites. But of course I’m still not entirely satisfied with it.

Bottle Quine

A quine is a computer program which takes no input and produces a copy of its own source code as its only output.

This one is not really a quine, but something similar, 1020 bytes of HTML/JS that animates it’s own code. Inspired by the great work of @aemkei.

Click here, to see it in action!

CSS Mesh

CSS Paint Worklet (Houdini) experiment to generate cellular noise based mesh.

Details on github.

Web Authentication API

WebAuthn uses public key cryptography (asymmetric) instead of passwords or SMS texts for registration, authentication and 2FA.

  • Protection against phishing: webauthn signatures changes with the origin, so it won’t work on “similar” webpages (with different domain name).
  • Reduced impact of data breaches: it does not really matter if the public key is stolen.
  • Invulnerable to password attacks: much harder to crack it by “brute force” than passwords.


The most widely used digital image format, developed by Joint Photographic Experts Group. Several attempts has been made to replace it with something “better” (JPEG 2000 included), but it still helds its position. ISO/IEC and ITU-T standard, which only specifies the codec, but not the file format - the Exif and JFIF standards define the commonly used ones.

QR Code

Invented by Denso Wave (japanese automotive company, subsidiary of Toyota) in 1994 to track vehicle parts during manufacturing. It was designed to allow high-speed scanning. Now it is used basically everywhere.

Portable Network Graphics

One of the most widely used raster image formats, that supports lossless compression, alpha transparency and is supported by all the webbrowsers. It was developed in 1996 as an improved, non-patented replacement for GIF (“PNG’s not GIF”). ISO and IETF standard.