I made one using this pattern and it was not hard at all. I was amazed with how well it all went together including setting the flower inside the giant circular opening to form the square corners. I had trouble with the very center of the flower laying flat where all the seams come together, so I appliqued a circle onto the center and cut away all the seams that came together under it. To make my templates I used the thin plastic sheet that comes in a package of bacon. Easy to see through when tracing the pattern and doesn't get "frayed" like cardboard does.
http://vintagepatterns.wikia.com/wiki/Yours_Truly_3919