- A real engineering notebook
Bound, numbered, dated. Forces you to keep a record you can't silently edit later.
- Mechanical pencil + good eraser
Unromantic, but the friction-free path from a thought to a sketch matters more than it should.
- Obsidian
Plain-text notes that link to each other. Outlasts any single app because it's just files.
- Desmos
The fastest way to see what an equation actually does. Underrated for building intuition.
- Git
Not just for code. A history you can branch, undo, and reason about is worth keeping for almost anything.