If I understand what you're asking, I don't see why it wouldn't be reasonable. You can do pretty much anything you want as long as you like it! Lol* If you mean you want to do three 8x8 blocks side by side, then I'm guessing to achieve the 36x16 measurements you're figuring in the border and sashing. Like maybe something to hang over a couch or mantle? Sounds ok to me! Hanging might be tricky, but I'm sure you can do it! :)