I took a class from Gyleen last summer. I have a bunch of the squares made but haven't finished my quilt yet. She is an engineer and designed the ruler herself because she was upset with the rulers on the market. You can buy the ruler from her or from Newark Dressmaker Supply and probably other places too. She has a couple different books out and a website. She is a wonderful person very personable. Loved taking the class just the hear her talk about herself and her family. The quilting was nice too.