The basic technique of stacking exact repeats of fabric and cutting to make a kaleidscope looking block are the same.
Stack-n-Whack was the first to develop the method. Others came later. OBW usually has no sashing between the sections. The first Stack-n-Whack design was the Kaleidscope Pinwheel. Other desgins came later - fans etc.
Both methods gave a new way to cut and piece kaleidscope designs. Prior to this, they were fussy cut using templates.
Stack-n-Whack is also a registered Trademark name by Bethany Reynolds.
Both methods rely on cutting exact repeats from the fabric. It is important to follow the directions exactly as while it might appear that the motif is repeated throughout the fabric, the only exact is down the fabric otherwise the registration of the motifs can be a little off and the finished product a bit off.