This looks a lot like a t-shirt quilt made from Andrea T. Funk’s book How to Make a Too Cool T-shirt Quilt, except sashing is added to the pieces. This method does not use stabilizer! The t-shirts are cut in multiples of 4: 4x4, 4x8, 8x4, etc to 16x16. There is a formula to determine the quilt size and a CAD (computer assisted design) program to determine layout. I don’t know CAD, so I cut representative blocks from cardboard stock, (the book recommends paper, but I could not get the small paper pieces to stay in place with my fingers) to determine layout. The book also shows how to quilt your quilt on a long arm. I took a class at my LQS and made two t-shirt quilts, and love the softness of the t-shirt quilts without stabalizer. However, I think the added sashing would change the dimensions and layout of the t-shirt quilt.