From Parallel Lines or other applicable formations.
Centers Trade & Roll as Outsides 1/4 Out, Trade & 
  Veer Out (Press Out).
Parallel Lines end in Facing Lines.
| 
 From Parallel Lines:    | 
| 
 From Twin Diamonds:    | 
Notes:
- 
Although Regroup can be done from any Parallel Lines, it is
    almost always called from Back-to-Back Lines.  This is
    primarily done because of flow considerations for the Outside dancers.
 - 
Outside 4 always end directly facing each other on the Outside.
 - 
The Outsides should pass Right-shoulders with each other.  Other
    glossaries may define the Outsides' part as 1/4 Out &
    Cross Cast Back [C1] 
    (hence implying a Left-shoulder pass).