These blow me away and I hardly know where to begin. The sheer amount of perspective lines and angles to consider is overwhelming, but you executed them beautifully. Trying to figure them out with my inexperienced brain could take a lifetime. (I'll have to start tomorrow because I spent a lifetime on some electronics stuff yesterday. )
There's something very appealing about the corner stairs, especially for many places I know where buildings either come together at obtuse angles or are oddly shaped by the streets they were built between. (Boston has a fair amount of that.) It would add a lot of charm to multi-unit dwellings.
The lower set of shapes or monuments is beautiful, and I especially like the rounded shell/giant color contact lens/hatch-shell-like thingy (forgive the technical term).
Finally, that awesome building is too beautiful and very bold. Great perspective on the top sketch, and adding people for a sense of scale also rightly points out that there would be lots of people coming to enjoy the place. My only concern is that all the extra surface area in the notches would make it expensive to heat.