My DD's University bedroom has the strangest windows due to the fact that the window wall is 45* to the one wall of the room.

It currently has a cheap blind which she uses for privacy, but having grown up with 100% block-out curtains at home, she isn't getting much sleep.

To add to my dilemma, we arent allowed to add anything to the wall which would require nails/screws/drilling. It needs to be strong enough to last the year, and then removed without damage.

I'll attach an image to show exactly what I mean.