That’s super interesting. It would have been some mainframe fortran from the 1970s because I remember him bringing me and my brother as children into a university computer lab where he had weaseled some time on a mainframe so he could punch cards. He told me the variable naming thing (and was prone to exaggeration) so it might not even be true - I can’t ask him now as he’s writing pseudo fortran implementations of Newton-Raphson with short variable names in the great computer lab in the sky at the moment.