Yes, pinning on this kind of block would help line up your seams. Also pressing the seams in the proper directions so that your intersections lock into place. I am not good at explaining, but I am willing to bet you get a good explanation on pinning this from one of the others, soon. When you sew these together, if you have pressed one seam up on the one piece and on the other the seam down, they want to naturally nestle together, and that does help with alignment. Can't wait to see this in black and white :)