A great article about K is http://archive.vector.org.uk/art10501320 http://archive.vector.org.uk/art10501320 - it introduces K as a magical, end-all programming

A great article about K is http://archive.vector.org.uk/art10501320 http://archive.vector.org.uk/art10501320 - it introduces K as a magical, end-all programming language that is blazingly fast and would solve lots of problems...if only someone other than the author understood it. As I understand it, the original K is closed-source and no one has really used it. All the derivative languages were reverse-engineered from programs and descriptions, and it spun into it's own family of APL-like languages. As far as I know, at least.