I heard a caller calling SETS IN MOTION from a LINE OF FOUR FACING IN. 
And also from INVERTED LINES. 
 
I believe that is not legal. 
Any comments??
The Centers part of Sets In Motion is based on the C4-call 
'
Single Hinge & Trade' which is a Hinge, Centers Trade, All Roll.  
The last part is a Roll, not a Face The Center!  
Hence, Sets In Motion can not be done in any Centers consist of In-Facing Couples.