These two pictures show 2 ways I can sew the blades together. The top one has the blades joined so that they form a solid line to match up with the hexie. The second pic shows another way to join them so that they match up with the corners of the hexie.
I use the top method just because it's easier to join with the center. What I do is join 2 blades together, and then attach each pair to the hexie.
And here is the finished block.
And another one: