Here a follow-up on today's blog (especially for Kristine from paperdollminiatures ;-)!
How-to-do the hinges was the issue...
I decided to use black electrician tape (very sticky and is a bit elastic) to attach the panels to each other. Then I covered this with the window frame pieces, made from styrene strips.
Note: I used double sided sticky tape to attach the frame strips to the acrylic glass - after messing up a first lot with glue... ;-)