I just finished covering cushions for a rocking chair. Since the seat and the back are different sizes, I would suggest that you draw on a wrapping tissue paper , the setting of your blocks. For a maximum effect, pick a large block 12’ or 16’ and put borders around it, till you reach the size you need. It seems like a lot of work but the time you will spend to prepare your ’masterpiece is worthed. If you choose repeat blocks make them in a small size 4 or 6 inches.
Too bad I cannot post a picture of my rocking chair, my course on computers has not reached 'How to attach a file' yet.