Yes – I believe the author took the Design Patterns book and went to town.

The classes were small (< 100-200 LOC), they fit together well, and the code was well tested. It was a SyncML parsing library developed in-house in Objective-C.

What helped, I believe, was him coming from a Ruby / RoR background (extensive OOP usage) and the fact that this was his 2nd attempt at writing this, after he wrote a similar library in Ruby.

I think about some code to this day and try to emulate wherever possible. Although I think the guy that wrote it was also a very smart person and experienced programmer, so I don't beat myself up if I can't quite make it to that standard.