Old Work on Backpropagation in ML

Just came across some old work that I've done, so want to share and keep it tagged for future references:

https://www.wolframcloud.com/objects/summerschool/pages/2017/TetyanaLoskutova_TE

Honestly, I've never needed this knowledge in practice but it helped me to understand a course on numerical methods. Not that I have much hope to ever use the knowledge gained in the course on numerical methods...