I've done a OBW using a 60 deg triangle ruler which made hexagons. For octogans it's a 45 degree ruler but you need to make squares to fill the gaps. The one I did was fairly straightforward and fun to do - I already have the fabric for a second one! My ruler was a Marti Mitchell
http://www.frommarti.com/mm5/merchan...ategory_Code=R I used the method in One Block Wonders by Maxine Rosethal.
K x