Lethal Swissair international travel adapter

This is something I purchased on Ebay in a lot being sold by a charity shop (which I literally bought blind, as the listing just showed a carrier bag full of lamps!) I mainly bought it because of one lamp that was visible in the listing, although I received an absolutely incredible surprise... (Pictures of both later) I have never seen another adapter like this, it's very unusual (and very complicated - I can't figure out how to switch the pins around!) and VERY 1970's!