miniblog.

The Shelf is a NeXTSTEP alternative to a clipboard, but more flexible and powerful: https://en.wikipedia.org/wiki/Shelf_(computing) You can put a source file and destination directory on the shelf, enabling a cut-and-paste style operation. You can still refer back to them afterwards!

Adding differentiation as a first class concept in Swift, enabling stepping through ML code and type safety:

Generating private keys for wallets, using poor seed data, enabling others to access the contents: