Comment by montebicyclelo

https://sidsite.com/

Reverse-mode automatic differentiation from scratch, in Python - https://sidsite.com/posts/autodiff/

Notes on training BERT from scratch on an 8GB consumer GPU - https://sidsite.com/posts/bert-from-scratch/

How the BPE tokenization algorithm used by large language models works - https://sidsite.com/posts/bpe/