They are all kaleidscope in style.
Stack and Whack is a or was originally a specific pattern designed by Bethany Reynolds in Maine. Other patterns have been developed using the same basic technique.
They all are based on cutting strips or squares from a certain number of layers of fabric that are exact in their design placement. Then depending on the number of layers you cut you fan out the cuts making the kaleidscope design. Before Bethany introduced the concept these designs were fussy cut to get exact motifs.
Bethany's first design was Pinwheel Kaleidscope which was modified later into many patterns using the concept.
I associate Stack and Whack with Bethany Reynolds and the many designs she has created even tho the technique of stacking fabric layers is common in all.
Stack and Whack usually has other fabrics in the block
One Block Wonder uses the same stacking concept peoduces a kaleidscope block but they are joined next to each other without sashing and many are arranged in a draduation of color or pattern.
OBW are usually 6 pieces in the block
Stacked Posie (if that is correct) usually contains four squares.
But they are all Kaleidscope in style.