Aha, then that's why I even was not able to reproduce the way I saw in some videos on Youtube. The two people that recorded it do it before it changed. I am afraid it did the puzzle even harder. People who are not able to solve it themselves cannot check the solution on the Internet. At least currently.
I did it the other day at last. It took me overaly about 3 hours and it was the most frustrating moment in a game in my life. I love the game and I want to play it again but I am really frightened to do that because I don't want to do it again.
Edit: Are you sure it is easier later and not on the contrary? Because the way the people went through in the videos seemed to be easier than I had to do in the end. Maybe it is a bug.