Kona, an open-source implementation of the K language

I can confirm this isn't an IOCCC entry. It looks like obscurantism, but it isn't. It's C code written as terse as possible, not as confusingly as possible. It takes a while to get used to. It's worth it.

There is significant overhead involved in learning to write C like this. There are also significant gains. It's similar to learning to use vim.

Last I counted the source was something like 250K bytes and still very manageable. If it had been written in a traditional style it would be many times that size and much harder to work with.

To answer myself, there's a lot of material here: https://anonymous:anonymous@code.kx.com/trac