Can you tell the Saxons what a "Wiederkehr" is?
It means an ancillary roof structure that usually meets the main roof structure at a right angle well below the main ridge. Basically a side street. And so I can't really imagine much under ...
Wiederkehr with flat roof, can be greened, usable as a terrace
... because "Wiederkehr with flat roof" sounds like a contradiction to me (as a philosopher, I hold the view that a snowball ceases to exist as such when you fry it).