Creative Grids Starburst 30 Degree Triangle Quilt 9-1/2in Ruler
Sew together twelve 30 degree triangles to create a complete circle; six to create a half-circle; or three to create a quarter-circle. Or, use the angles to create a variety of intricate 12in finished blocks - no paper templates required!
Instructions: https://s3.amazonaws.com/checker-cg/instructions/CGRISE30_Instructions_Website.pdf