Kimberly Enmo has a flying geese ruler which is easy to use and requires no waste or trimming. See her website for a video on how to use it. It is a 2 sided ruler. Cut the triangles on 1 side and the squares on the other side. The only thing that you have to be careful about is that the strips that you use to cut the squares must have right sides together to make mirror image squares. You can purchase the ruler on Amazon. Cuts the time in half and you usually have little or trimming.
Dottie