FORTRAN II was a version of Fortran in use from 1958 to 1961, then superseded by FORTRAN IV. (IBM never published FORTRAN III, it was only an IBM internal project.)

https://en.wikipedia.org/wiki/Fortran#FORTRAN_II

Its amazing to me how few instructions it took to write this. I would love to see higher level documentation of how it all fits together.

you buried the lede in the lead, where it links:

See also LISP 1.5

https://texdraft.github.io/lisp-1.5/listing.html

finally! being able to take the actual CAR and CDR!