I'm not sure what the difference is between OBW and Stack and Whack. I've done a couple as well as a 4 patch and found them really fun. the OBW with triangles is considerably more time consuming, but I love turning the pieces to decide which I want in the center, and then experiencing the fun of:"Oh! Look how this turned out!!" Each one is a surprise. And if that's not enough, then deciding how to layout the blocks is yet another creative experience. This quilt is really beautiful,by the way!