After seeing that ruler, reminds me of a block I did for the BQ3 pattern.

If it was me, I would take 2 layer cake squares, place one on top of the other, measure in 4" from the top left and 4" from the bottom right and cut using a long ruler. And swap the cut pieces around. That's how I did it for the BQ3 pattern - did not need a special ruler. https://www.google.com/search?hl=en&...99.Up2dVKtriQU