Is this picture what you are trying to accomplish?
https://4.bp.blogspot.com/-FTuaiT4-B...0/IMG_0849.JPG
If yes, you can cut your pieces with this ruler, turning it back and forth to cut each piece.
https://www.quiltinaday.com/shoponli...t-in-a-Day/708 It will only work if your fabrics go out to the edge. Won't work if the inner or outer points are floating