Not to mention the various graphical programming languages used in industrial control - ladder logic, continuous function chart, and sequential function chart.

Not to mention the various graphical programming languages used in industrial control - ladder logic, continuous function chart, and sequential function chart. Ladder in particular is incredibly widespread, as it was a direct descendant of the diagrams used to document and debug relay logic, and was adopted in some of the first PLCs (programmable logic controllers) in the late 60s/early 70s. Programming PLCs sometimes feels like going to, say, Australia or New Zealand, and being immersed in an environment which went down a different evolutionary tree very on in its development.