I recently purchased a Martelli mat. I cut out a bunch of squares and saw that they all weren't the same size. I thought it was me, a friend came over and used it, same thing happened to her. We got out a few rulers and measured the inch marks and some were off by 1/16 th of an inch. Then we used a yard stick and a measuring tape and discovered it wasn't 36" long either. I have called Martelli and am waiting for a call back.