The 12 variations on "the crab" may, for the sake of clarity and a more efficient warmup routine, be organized into 3 sets of 4 patterns as follows: the basic pattern, its retrograde pattern (reversed order), a rotated pattern (top line shifted), and a retrograde rotated pattern. See PDF here

Respective to the Crab Variations from my last post, the sets would be grouped:  {1, 12, 2, 11}  {3, 8, 4, 7} and {5, 10, 6, 9}