What about trying some color celophane cut to shapes, and a dab of glue to hold onto the window?

Adorable and very creative!

Did you finish your window yet? I'd love to see a picture!

No....not yet. It was calling to me this weekend (now that my elbow has calmed down) but I'm in a time pinch on a quilt for a wedding gift so it's been de-prioritized for now. Wedding quilt comes first, and it's not going so great. (Always how it goes...work with no deadline goes smooth as glass. Put a deadline on there and everything goes to heck!)

I WILL finish it sometime, though, and I WILL post pictures!

Wow, what a great idea! Awesome & love the selfie.

I have no windows in my sewing room, if I did, I'd definitely imitate your idea. I absolutely love it and am looking forward to seeing the completed project. Plus, I love blues and browns together. The wedding quilt will be given away (and you likely may never see it again) but the window will be with you for years to come, so relax and have fun with it all.