It's a 9 degree ruler (as in 1/20th of a 360 degree circle). The pattern works with a 10 degree ruler, too. I've seen a template for it, but I'm not sure where. It was made in 2 pieces because of the long length.
I think this is it.
http://hkfstores.com/content/freeprojects/Poppies.pdf
The quilt pattern is poppies. I'm not sure if it's the 9 degree or 10 degree ruler, though.