I have just finished a quilt and now I don't understand about seam allowance.
My blocks are 11 inches square. So for the side sashing I cut 11" X 2.5" strips and sewed the blocks in rows.
Well in my figuring and dyslexic brain..LOL I cut 20 strips since I have 20 blocks..LOL
Then I wanted to do the bottom of the blocks. I am only putting sashing/cornerstones in the middle.
I cut red cornerstones at 2.5" square...and attached them to a strip of 11.5 strip. Now using my brain I thought I would just put one strip and one block to see if it lined up.
Nope it was to long. so I cut .5 inch of the strip and added another 11 inch strip and it fit.
So why did it all fit? I am grateful to use up the other strips I used. But I still don't understand why I didn't need a seam allowance.