I don't believe they are. If the blade in the pattern is pointed, use the length to the tip of the blade as a length measurement (it will include your seam allowance). Make note of this length measurement. (The sides and other end are to be cut according to the pattern.) Cut straight across at the length measurement. Fold in half lengthwise and stitch across the end. Then turn it to the right side and fold, making the middle of the blade into the pointed end.
When the blades are attached to each other, you will need to backstitch in order to secure the seam. Then when, quilting by machine or by hand, make sure your quarter circle covers at the "secured seam" area just mentioned. This method will allow the pointed part of the blade to be three dimensional and self lined.
I suggest you try this method with scrap fabric to work out any problems. And if any of this is not clear, I will try to explain again. S