It's amazing what a little brown paper and an afternoon can do to a window. I love this technique...I made a headboard like this years ago. I don't think it would be good design to have a paper head board and a paper window frame in the same room, but maybe you could do a bunch of paper things and make it look like an art installation. It could also be cool to use wrapping or wallpaper if you want colors or prints.
I made this in three parts - the top, and each side strip individually. I folded the top strip gently in half and free handed some curves. I used a rotary cutter and I would recommend one for this kind of project.
I thought about making the sides match the top, but I share this office with Mr. W and I wanted to keep it somewhat simple to cater to his tastes too.
All in all, it makes me happy. : )