I am pleased you responded with more etymological information. For some reason, knowing that kind of history really brings these things alive for me. I am enjoying the series.

I hope at some later date there might be a connection to regular grammar and regular language. I've always been fascinated by the connection between Noam Chomsky's linguistic work and the simultaneous development of Lisp at M.I.T.&mdash;both endeavors being obsessed with recursion.