I ordered a clear hard cover for my IPhone from Ebay a while ago. This cover is made for tuning and really wanted to use my washi tapes for this. In the photo below you can see what I needed.
First I picked out the washi tapes I wanted to use. I cut out a piece of paper in the sizes of the cover and covered it with the washi tapes. Then I just popped the paper inside the cover and then the phone. That’s it!
Of course these ideas are endless. I’m thinking of using photos, maps, pages of dictionaries etc. Just let you imagination run wild.
-Alina
Alina 
Brilliant idea! I’ll get back to you about this. 😀
I want one as well, you see.