My goodness how did you figure that out? I don't know that I fully understand what you said. Let me try and summarize. For each 12 inch block she has
6 x 2 1/2 x 15" strips which she sews into a panel. Is that correct so far? Are these sewn into a cylinder and then subcut into 2 1/2" strips, and for each 12" block she moves the top square down one? I don't get your second paragraph about the diagonals. I looked at the quilt again and wasn't able to isolate a block.