I feel that a puzzle that isn't fully parsed isn't really solved. So, spurred on by zabadak's post I went away and parsed 26d only to come back and find that others had posted. In the meantime. I also hadn't parsed 31 but now I have. But apart from the (I think) fairly obvious shading, I haven't yet got a clue about the rest of it.
Enlightenment will no doubt follow in the morning for tomorrow is, I'm told, another day.