Although visual programming languages have been a subject of research for at least thirty years, they have failed to make an impact on programming language design in proportion to the enthusiasm of the investigators in the field. Semantics of such visual languages can only be understood through reference to the semantics of the underlying textual languages. On the cruelty of really teaching computer science . ACM 32, 13971404. In much the same way as pointers for beginning programmers, understanding concurrency requires a conceptual leap on the part of students.
Nachos helps in two ways.