The ideas for a language which could serve the dual purpose of system description and simulation
programming originated at the NCC in the spring of 1961

I have rather clear ideas on how to describe queueing systems, and have developed concepts which I feel allow a reasonably easy description of large classes of situations.

КЛАССЫ СИТУАЦИЙ

По ссылке документ, в котором можно увидеть, как разработчики Симулы выходят на основные концепции ООП.

hannemyr.com/cache/knojd_acm78