the "useless" language. Quite a crazy language - something like Forth, but all commands and syntax consist of single characters. There are also quite strange restrictions for function definitions (maximum 64 characters per line and only one if or while or similar in a function). Particularly fascinating is the U->C compiler written in U. The developer of the language has written an entire book about programming in U. But beware: the author's color choice is an acquired taste ...