Yes, I guess that would be thread painting. It would be over every seam. You would probably want to press the seams open. It certainly is a lot of thread and time. The link to the denim quilt was interesting. However, I would not want to work with all that 'sashing'. Looks like since you are drafting, that you will be continuing to go with your own tile design. I think that is great! Looks to me like Y seams too but maybe there is another way? Maybe with one patch of the same fabric being made by a seam? I'm not sure if that is ever done.