Daniel Pfeffer wrote:
It brings APL to mind. AFAIK, the first write-only language by design.
Actually, it was developed for blackboard use. Kenneth Iverson was teaching matrix math at Harvard, as an extension of the classical math operators, as a notation for math expressions involving matrices. He was using it as a lecturing tool for several years, until someone at IBM suggested that just like a computer program could process plus and minus, it could handle matrix inversion and stuff like that - all those special symbols Iverson had been using on the letcuring hall blackboards. APL is like user friendly Unix: Unix is user friendly - it is just somewhat picky in who its friends are.