You can certainly make them rectangular. I took an actual postcard for the size of my travel quilt.
As far as formulas, I don't know... I go by graph paper and eye. My bars are kind of narrow for some folk and wide for others, but the look I was trying to get was the old scrap books with black pages.
Last edited by Iceblossom; 04-15-2025 at 04:36 AM.