From Random Forests to RLVR: A Short History of ML/AI Hello Worlds

Two years ago, I posted a list of Hello World examples for machine learning and AI on social. Here, the Hello World means beginner-friendly examples to showcase a method. I set a biennial calendar alert to revisit and append to it. I was thinking pretty hard about what a 2025 example could look like. So, here is a short post with the updated list and some explanations for more context.