
Given the nature of the solution to this puzzle, perhaps that's supposed to be intentional, but it's a little weird - if it is intentional, it'd be nice to have some kind of message pop up about how "you can't seem to go forward through the gate" or something.
Secondly, and perhaps this is just related to how I solved that puzzle, but I had solved it via liberal use of the Portal spell, went through the rest of the tower, to find that I had gotten there too "early" for the game, and had to come back later once there was an actually-related quest that I needed to have in my journal... Because of the way I solved the puzzle, though, when I got back into the tower, I found all initial gates closed, and I could no longer get to any of the levers! (I had since reassigned all the Portal locations I had used previously.) It'd be nice if there were some method of "resetting" the gates to their initial state, so that I'd be able to proceed through there without resorting to the old deleting-the-relevant-map-file-from-the-savegame-slot method.
(Then again, perhaps that too is intentional.)