The idea is absolutely amazing and bot nearly as difficult as those rugs that use the round rope stuff.
Then you lay the strips of batting inside the jelly roll strip and sew it all together.
You will continue this method until the rug grows into the desired width.

Image By: Peace And Applique Via YouTube
This rug is the coolest sewing project that I have found in a while.
I really cannot wait to make it!
https://www.youtube.com/watch?v=co6DzlMX7hMFabric Strip Rug

