fn main() -> Result<(), Box<dyn Error>> {

Feiko
Wielsma

Programming Instructor

I teach C, C++, Python and Rust in Utrecht, usually to small groups and often to people who were convinced they weren't "technical enough". Before that I spent six years writing embedded software, so my examples tend to involve hardware that can actually break.

How I teachSay hi
Feiko Wielsma
let me = Feiko::new();

Dropped out of game dev. Now I teach the scary parts.

I started out studying Game Technology at Utrecht University and left after a year and a half. At nineteen, the maths, the logic and the functional programming scared me off. These days they're my favourite things to teach, which I'm choosing to call character development.

I switched to Technische Informatica at Hogeschool Utrecht and landed in embedded software: first at OPNT, an Amsterdam startup doing precision time synchronisation, then at E2M Technologies, whose motion simulators throw grown adults around for a living.

Wherever I was, I ended up being the one explaining things: to classmates, to strangers in PC-building Discord servers, to colleagues at the whiteboard. At some point it made more sense to do it on purpose.

Over the past year most of my own code has been written with an agent in the loop: Claude Code, Codex, Cursor, Antigravity, whichever one is winning that month. It changed how I work more than what I teach. Somebody still has to read the diff and spot when the model is confidently wrong, and I'd like that somebody to be you.

#[derive(Debug, Clone)]
struct FeikoConfig
location
Utrecht, Netherlands 🇳🇱
employer
SpiralTrain
group_size
Small enough to learn every name
pair_programmer
Usually an LLM
agents_in_rotation
Claude Code, Codex, Cursor, Antigravity
side_quest
Always one running. Ask.
last_updated
let history: Vec<Role> = vec![
  1. 2025
    Programming Instructor
    SpiralTrain
  2. 2021
    Embedded Software Engineer
    E2M Technologies · motion simulators
  3. 2019
    Embedded Software Engineer
    OPNT · precision time synchronisation
impl Feiko { fn languages() -> &'static [Lang] }

What I teach, and what I build with

use lang::*;

  • Python
  • C
  • C++
  • C#
  • Java
  • Rust
  • Perl
  • HTML/CSS
  • JavaScript
  • SQL

use devops::*;

  • Git
  • GitLab
  • Docker
  • Linux/Bash
  • OpenShift

use ai::agents::*;

  • Claude Code
  • Codex
  • Cursor
  • Antigravity

use ai::stack::*;

  • LangChain
  • TensorFlow
  • n8n
  • ChatGPT
  • Gemini
  • Claude

use embedded::*;

  • Raspberry Pi
  • Arduino
  • Wireless/IoT
  • Real-time OS
fn teach<T: Curious>(student: &mut T) -> Growth

How I teach

Small groups, on purpose

I teach through SpiralTrain, in groups of eight or fewer. That's enough people for a good argument about semicolons, and few enough that nobody quietly drowns in the back row.

≤ 8 students

Built around your actual problem

Python scripts, C pointers, C# apps, the Rust borrow checker. If the group needs something else by Wednesday, the plan changes by Wednesday.

multi-lang

Fundamentals, now with agents

Claude Code will happily write your for-loop. It won't notice it leaks memory. I show where these tools save you hours, where they quietly cost you days, and which fundamentals you need to tell the difference.

ai-assistedAsk me about it →

Why I do this

I've been explaining things since university, mostly unprompted. The moment something clicks for someone is still the best part of my week.

origin story
mod human { // the non-code bits

Off the clock

Kesong

4 kg Peekapoo: Pekingese, poodle, and a street dog nobody will own up to. The name is Chinese for croissant.

WoW raider

Raiding since before it was retro. Healer main, and there's a raid hidden somewhere on this page.

Virtual pilot

Microsoft Flight Simulator, departing Schiphol by preference. Landings are negotiable.

Tiki cocktails

Rum, citrus, orgeat. The holy trinity.

Watch collector

Fake ones. The vibe, not the vault.

Agent wrangler

Usually one coding agent writing, another reviewing, and me deciding which one is wrong.

Hobby of the week

Right now it's probably soldering something. Ask again next week.

PC builder

Went from answering build questions on Discord to preaching cable management in person.

Utrecht, NL

Bike lanes > highways. Stroopwafels > everything.

Arch, btw

Yes, I had to mention it. I like knowing what every package on my machine is doing there.

Polyglot-ish

Dutch and English, some German and French, beginner Chinese. Mostly dog-related vocabulary so far.

assert!(students.iter().all(|s| s.learned_something()));

Straight from the course evaluations

I really enjoyed the Python programming training! Feiko explained everything clearly, and the examples made it easy to understand even the tougher topics. The sessions were well paced and practical, so I could apply what I learned right away. Really helped me feel more confident using Python.
SandyaPython
De trainer Feiko was betrokken en had veel kennis over de taal en wist dit goed en enthousiast over te brengen. Alle nieuwe onderwerpen zijn besproken en afgewisseld met het maken van oefenopdrachten.
Kees
Advanced C++
Feiko is een kundige en aardige trainer die zijn lesmateriaal op mijn behoeften kon afstemmen. Ik heb er meer kennis opgedaan dan ik vooraf had verwacht. Ik kan de cursus alleen maar aanraden!
Stijn
Machine Learning met Python
Leuke cursus over programmeren in Rust. Wel veel stof in weinig tijd — maar docent Feiko wist het goed te brengen.
Marcel
Rust
Feiko heeft duidelijk veel kennis en ervaring waardoor hij goed kon uitleggen en de belangrijkere onderwerpen kon onderscheiden. Cursus werd deels op maat bijgestuurd tijdens de week — dat was top.
Victor
C++
New stuff, interesting, very good explanation.
Ilir
Deep Learning with TensorFlow
Well planned course and flexible learning.
Umer
OpenShift Container Deployment
Ik heb een uitstekende en persoonlijke cursus ontvangen. Feiko is een hele goede trainer. De theorie werd me duidelijk uitgelegd en de oefeningen waren eenvoudig genoeg om de essentie te begrijpen.
Marisol
Perl
Ik kreeg 1 op 1 les over C++. Er was aandacht voor mijn kennen en kunden. De docent was flexibel en maakte nieuwe opdrachten aan wanneer nodig.
Wessel
C++
Goed ontvangst en goed bereikbaar. Veel stof ontvangen en tempo wordt aangepast aan het niveau.
Aulia
Python
De leraar heeft de stof duidelijk en gestructureerd behandeld. Alles was goed te volgen en de uitleg was helder.
Cristian
Python
Leerzame cursus in een prettige en persoonlijke omgeving.
Hanneke
C++
Docent Feiko is kundig, vlot en zeer gedreven. De demos zijn talrijk en er is voldoende kans om de theorie te oefenen.
Martijn
Advanced Python
1–3 / 12
fn contact(msg: &str) -> Option<Reply>

Open an issue

Questions about a course, an idea for a collaboration, or strong opinions about the borrow checker or fake Rolexes. All welcome, and I read everything.