It is so easy, BUT...
There is always a "but" isn't there.
You do have to be careful at what design you put together. It works fine if you do square blocks, or hourglass blocks or even a zigzag pattern.
What does NOT work is a center square with "concentric" rings around it. Although you can lay it out that way, the "seams" don't come together right because allowance hasn't been made for the seam allowance.
Ask me how I know ....