Traditional blocks are in the public domain so if you are wanting to enter it in a show & need to say that it's not covered by someone else's copyright, you can do that.
If you're wanting to enter it into a show in a category for "original design", you'll need to read the criteria. Typically, simply turning the blocks in a different way or creating a sampler of different traditional blocks or even enlarging/reducing blocks is not sufficient to meet a show's criteria for original design. I've seen a few times where that's been allowed if the new layout creates an original secondary pattern, but even that's atypical. I would contact the show's coordinator if you're trying to decide which category your quilt goes into.
If you're seeking legal copyright protection, you'll want to contact a licensed attorney with focuses in Intellectual Property Law, but generally my first thought would be "no". You could create a set of instructions & get a copyright on those (probably), but the design itself separate from the instructions usually wouldn't be protect-able. The main legal question used to determine whether a design copyright/patent is enforceable is whether the average person would find it "the same or substantially the same" as other quilts either in the public domain, or with existing copyright or copyleft protection.