I you have enough material you could make another border, just like the one you have now that goes between the block rows and then add a solid black 1 in there too just to put between the 2 or if you don't have more of that fabric add a black row and a light blue row between each one with the border you've already made and then around the outside. This would give you added length and width either way. It turned out really nice in the 2 color scheme.