I have taught classes on the stack and wack. Like wall paper, fabric has a repeat of the pattern, you need 8 repeats of the pattern. you have to do precise pinning, before you cut your strips. After you get all your wedges sewn together, then you just add triangles of a coordinating fabric to make them square. Every block is different, I love hearing all the ooh's and aw's of the ladies after every block is made. The classes are really fun.

Thanks...I've been wondering about this myself.