I hated that tool. In homec class we were required to use it and I just marked my project with a pencil for the darts. My item was perfect but the teacher marked me down because she said I skipped a step. I told her I marked the seam but she said she couldn't see it. -- I helped my friend on her robe. Actually I made most of it. We got an A on it. I got a B on mine because I didn't use that awfull tool. That was 41 years ago.