You can make it either 7 inches or 10.5 inches fairly easy. You'll be working with some fairly small pieces though. It's the size it is because it's 7 squares X 7 squares and at 2 inches finished per square that makes a 14 inch block. If you go down to 1.5 inch squares that'll make a 10.5 inch block and 1 inch finished squares that'll make a 7 inch block. The HST triangles are easy to do since you just add 1 inch to the finished size.