Flutterby™! : Deadlock Empire

Deadlock Empire is a cute little game of stepping through code to see if you can create deadlocks. At least one of the first few challenges involves discovering the interface to expand out how an instruction is actually executing, but as I work on a large code base that has lots of threading, but not a clear strategy for managing that threading, I wish the previous maintainers of this code base had played this game...