Quilt-A-Long

I decided to participate in Amanda Jean's quilt-a-long. It's already on week 8, but I decided to start anyway and see if I can catch up. She's posted instructions for one block each week on her blog, Crazy Mom Quilts (it started way back in November). I think this might be a great way for me to practice and MAYBE get better at this. I started tonight and I've finished block one, and I've got block 2 and 3 cut out. Not a bad start. Block 3 has triangles..YIKES! Could be a mess! I'll post pictures as the blocks are completed. These blocks are supposed to measure 12.5 inches. Mine are about .25 inches shorter. I wonder if my quarter inch seam isn't accurate?