Kona is a new open-source implementation of Arthur Whitney’s K, an ASCII-based APL like language. Kona is a fully working version of K3.
If you haven’t every tried APL/J/K or ilk you might find this language incomprehensible at first — unless you like a challenge! Watch the screencasts or read some of our earlier APL/J stories.
Regardless of your interest in K, any LtUer worth his salt will enjoy the source code. We wrote a bit about the history of the remarkable C coding style used in the past, but I can’t locate the link at the moment.