Thank you! I found it, and now I'm heading on to level 2!
awww man.. I'm now stuck at the "rotating room". How to even get out of there? I found the marks on the walls but I can't seem to get out of the room.
EDIT 2: I don't know how, but I got through. Alslo, what does the sign at the top floor mean? It says: "If you're stuck consider revisiting previous rooms" I went through the level again and didn't find anything useful. Any hints?