This is an implementation of the Nock 5K spec with an accompanying
interpreter.
Nock is a tiny stateless virtual machine that can be thought of
as a functional assembly language. Nock is the lowest layer in
the Urbit stack. On top of it rests the Hoon language, in which
the Arvo OS is written.
More on Urbit: http://www.urbit.org/
More on Nock: http://www.urbit.org/2013/08/22/Chapter-2-nock.html