...that looks like a diagrammatic representation of the Montréal passageway network (La ville souterraine, it used to be called, I think).
... I'm intrigued by the severe abstraction of maps like this:
It is still called that Dennis. I have been approached several times with the idea of a producing multi-level pictorial representation of this unique urban feature that is called the underground city. I have never been able to quite wrap my mind around it. ( I even toyed with the idea of a worms-eye view, looking up the skirts (so to speak) of people navigating the network). It's real complicated. Recently someone produced this very abstract map. Though I generally dont like abstract maps, I thought this one worked very well, at least for going station to station. No one as yet has figured out how to convey a sense of its depth.
Are you looking for a copy?
As for the picture you pasted, I love your term 'severe abstraction' ...as in 'severely' demented!. If you are willing to put up with the pain of turning it as you read, it does kinda work. I wonder how far one can push the envelope? We should hold a contest on Carto talk. How strange and abstract can you make a design and yet still conserve a basic direction-providing functionality ?
Maybe this thread will go from 'Bad map's to 'Weird maps'