Help, please, understand

[Amateur]

That's got a two-sided sketch on cardboard thickness of 1 mm in size 25h36 see on one side - the steppe landscape, from which a really blows heat. And on the back - Zaporozhye Cossacks. Signatures and inscriptions no. The paint layer is kept very firmly, no cracks, or talus. Soil as is not, apparently, just missed varnish. Letter sweeping, not too pasty. At the edges are not spelled out. As cardboard sketch at least 60 years, and even Pobol. About the possible co-sponsors, will likely be difficult to say, I was searching on the Internet. Not one artist has a style of writing. But maybe someone experienced forumchan still prompt?

And the next question concerns dominated the landscape of strange buildings, from which there is a fence. What is it? Walls, obviously, with the mud ligation of the branches. The form is clearly round. Live in it can not - no windows. For the hive too large. Room for cattle? Then why round? For defensive towers watery, and no loopholes. Toilet (sorry)? But there is no exhaust pipe. For the same reason, not suitable as a silo or a forge. Perhaps, forum from Ukraine will be able to tell what is it? The construction is clearly not modern, perhaps, the definition of its functional role will accurately date the sketch ... Thanks in advance.