The article talked about building a basic version of an LLM. Even basic versions like Karpathy's TinyStories ~100 million parameter models which manage to generate comprehensive English for a restricted vocabulary are trained for hours on an A100. If you want to skip the nvidia/torch stuff you'll be both training for days and having to write your own training code, which is not going to be just 500 lines. The principles are simple - but that is true for any important algorithm of the last 100 years. As opposed to LLMs, most of those can actually be done in a few hundreds of lines of code with no specialized hw and software stack required for it to be practical.