Instructor: Mary Derry Terrific Triangles is Class 2 in Mary Derry’s super-popular quilt making series. Both confident beginners and experienced quilters can learn several techniques for piecing triangles while making a child/lap/table topper quilt in this class.. The Terrific Triangles project is a small quilt that is the perfect size for a baby quilt, lap quilt, or table topper. In ...