Oh and it's key is through a wall you can just walk through around there. I hate to spoil the puzzle, but this is a softlock otherwise because it's a very fine detail in what looked to be a completely different kind of puzzle.
Oh, and the 6 stone puzzle? It makes no sense. The only solution I've found is to do the order, RELOAD THE ROOM then move the middle left stone to the right. idk what's wrong with it.