THE TRI REC RULER IS NOT A 60 DEGREE RULER!!! Sorry, didn't mean to shout! The picture in the link is made using a 60 degree. YOu need to get a different ruler, or, you can use the 60 degree mark on your 6X24" ruler. Looking at the size of the triangles in the quilt, however, I think it's going to be much easier to get the correct ruler. Creative Grids has a 12" version.