Eh
Well, did't expect so many controversies.
I long wondered what Kram ment to say by "flash". Well - it is Nile-shaped opening in the wall. Waves. Hmm. Tried still surface, but it seemed boring to me, now it is like a temple on flowing river, and that is good

. Openings in the "ceiling" - yes, they are narrow gaps overlooking the sky.
Thanks for comments.
I will now improve the maps (that will take time) and probably finally render it for print.