or here's one with stars. You have to match the blocks up at the corners, but there's no way you can mess up and cut the star points off:
http://www.cluckclucksew.com/2011/06...ar-blocks.html
if you sew them all, you can square them all up to the same size in the end and make the final assembly a snap.
ETA: oh, I see I'm a bit slow today and something similar has been already posted!