[godshatter]

When I'm working with equations in my head, which I don't do often, I think of them as a list of terms and what's done with them. No visual representation, just a memorized list. For electronic circuits, I would probably remember what connects with what, but not how they are laid out spatially. For textbooks, I do remember sometimes that the specific text I'm think of is found on a left page near the top, but I can't see it. That's just where my eyes will scan when I look for it again. Most often I don't, though, unless I poured over it a lot when learning it.

I doubled majored in math and cs in school, and I found that the 400-level math courses were easier for me than others and I think it's because most people were trying to visualize things that were hard to visualize. For me, it was just another equation to work with.