Doesn't look much different, but significant effort went into the interim step.  The piece was disassembled and re-configured somewhat.  Now the outer shell pieces can swivel independently of each other as well as the inner column.  I have these two dyed Tiger's Eyes and am thinking of how I might use them on the inside for the shell to rotate around.  I envision them mounted in a staggered arrangement, or back to back, giving the effect of a bead. (!) For contrast of metals I may use silver and brass on the inner column.
The next design issue are the transitions to the neck piece.  I am thinking of repeating the rotating shell forms, scaled down somehow.  This would give three elements with free rotation about the neck and would give the sensation of rollers as the wearer moved and turned.