yet another source of inspiration…
Last summer I let Google’s CP-SAT solver crack Sudokus in fractions of a second. Deeply satisfying. Educational? Not really. The solver learned nothing, and neither did I. It just knew. That is also my problem with every Sudoku app I have tried. You get stuck, you tap “hint”, and the app says: “Row 4, column… Read more Teach Me, Don’t Tell Me: A Single-Page Sudoku Trainer
I was 13 when my first computer showed up: a Commodore 64. Beige, heavy, slightly warm after ten minutes, and — the part that really got me — it could make music. Not beeps. Music. The chip responsible is called the SID, and it has owned a corner of my heart ever since. Years later,… Read more One Page, Three Voices, Zero Regrets: My Browser SID Player
My C64 had already done the damage. By the time I entered the ‘Kanti’, I was firmly convinced that computers were the most interesting thing in the universe. The one thing the Brotkasten could not do was come to school with me. A Sharp PC-1403 could. Twenty-four characters of LCD, a real BASIC interpreter, a… Read more My Companion Through the Gymi Years
If you ever typed LOAD “*”,8,1 without looking it up, this one’s for you.This is a small experiment in vibe coding: using HTML, JavaScript, and a bit of Antigravity to build a deliberately stripped-down C64 “emulator” that doesn’t aim for accuracy — just for maximum nostalgia. No full emulation, no perfection, just the feeling of… Read more Vibe Coding the C64: Maximum Nostalgia Under Minimal Constraints
Somewhere between Advent candles and Christmas cookies, a strange phenomenon hit our household: pixel fever. The kids wished for pixel art from pixeln.ch for Christmas — not plush toys, not consoles, but gloriously rigid grids of colored squares. At that moment, it became clear: this was no phase. This was discrete geometry taking over family… Read more A Pixelated Christmas Gift
It all started on a rainy afternoon when my kids asked a very dangerous question:“Dad… can’t we turn our own pictures into pixel art?” That question triggered what every developer-parent knows too well — a new side project was inevitable. A Small App with a Big Creative Goal So I built a small pixel image… Read more A Geek’s Love Letter to Pixels
I recently hacked together a delightfully simple micro:bit app that converts ambient light into sound. Think of it as a poor man’s photodiode oscilloscope — or, more accurately, a light-controlled Geiger counter for photons. The idea is straightforward: more light → faster clicks. What the Code Does (in Human Terms) The micro:bit constantly reads the… Read more Turning Light into Clicks
In this post, I present a solution to the Rush Hour problem appying A* algorithm developed with ChatGPT. A human programmer would typically use more descriptive data structures to make the code easier to follow. The initial solution didn’t work because the problem instance itself was invalid, but the algorithm was correct. Attempts to prompt… Read more Solving Rush Hour using A*
Over the past few months, I’ve shared a couple of Sudoku solvers here — some built with Dynamic Programming, others with Mixed-Integer Linear Programming (MILP). Both approaches work and are great learning exercises, but they each have their quirks when it comes to constraint formulation: This time, I wanted something cleaner — so I turned… Read more Solving Sudoku with Constraint Programming
For years, my Android unlock pattern was my fortress — a carefully chosen sequence of swipes that I thought only I could remember. Unfortunately, I underestimated two things: (1) the persistence of children, and (2) their uncanny ability to casually “observe” without being noticed. One day, I realized my long-guarded pattern had been compromised. My… Read more Mobilephone Unlock-Pattern Generator