I'm so glad that you posted this thread. I bought a wedge ruler after seeing this tree skirt pattern
http://www.sulky.com/project/treeskirt/ The ruler I bought was an Omnigrid on sale at Joann's and and is seen here:
http://www.prym-consumer-usa.com/bra...ITEM_NUM=RA624 I didn't know if the true wedge shaped one would be easier than this rectangular one with the lines. It's still wrapped in plastic in the closet. Maybe next Christmas? :-)