The Thue programming language was invented by John Colagioia in early 2000. It is named after the computational regimen it is based on — a pure string-rewriting process called a semi-Thue grammar, which is named for (and possibly created by) the Norwegian mathematician Axel Thue (pronounced "TOO-ay").
Thue represents one of the simplest possible ways to construe constraint-based programming. It is to the constraint-based paradigm what languages like OISC are to the imperative paradigm; in other words, it's a tar pit.
thue.c in the Thue distribution