I am currently making this quilt. I have discovered the greatest ruler ever. Even though I rarely see Jenny square her blocks, I always do. I use the Bloc-loc ruler to square up my triangles. It has a groove on the bottom which locks on the seam and doesn't let the ruler slip. The triangles made from sewing the 2 charms together end up being 2 1/2" unfinished. This ruler is a bit pricey but worth every penny. I used to be frustrated making hst's because of ruler slippage when trying to square them up. Not anymore.