I studied the picture. It is a DP. It is sashed with dark and a white square cornerstone. You would add two triangles on the end of each sashing piece (flying geese) to create the star look.
Cut the sashing piece the same length as the DP square. Cut the cornerstone square the same demention as the width of the sashing. Cut the small squares to make the flying geese ends one half the demention of the width of the sash.
I hope I described it so you can understand the construction and sizes to cut.