sentences:  Much of his energy was devoted to developing new kinds of teaching materials based on POP-11 and Poplog for students learning AI and cognitive science.In 1991, after 27 years at Sussex, he was offered a research chair in the School of Computer Science at the University of Birmingham, where he started a cognition and affect project (later on the Free Open Source Poplog Portal) and is still on it.He retired in 2001, but continues working full-time.