I just went through some of my old Mathematica notebooks and was amazed that they all still work.

Here's a screenshot of a notebook made in very old version....maybe back in the 90s? A few years later I re-used that notebook to make this blogpost about loss functions used in Machine Learning.

This kind of support for continuity over decades is amazing, and unprecedented in the open-source world. There's a new hot graphics library every few years, and the old ones get abandoned, so the old code does not work anymore.

This gives me faith to keep important ideas in notebook form, knowing that I can come back to them decades later, maybe when I get bored of software engineering and decide to teach.

Good job Wolfram Research, please keep up the good work!