With collections of small, very general primitives, we can combine them in ways to build
English dictionary recursively defined from just 60 words | Hacker News
... entire written languages
... entire programming languages
The Grammar of Graphics | Leland Wilkinson | Springer
... entire systems of graphical expression of data
... entire design systems
... or parsers. Parser Combinators
Each “zettel” (aka note) can only contain a single thought. For index cards, that’s a limitation of its physical size. But software encourages short entries too, as well as the branching/splitting of zettels. This makes it unlike a Wikipedia page, which is more like a book chapter or article. You could think of Wikipedia articles as being molecular; zettel entries are atomic.
... note taking systems?