This "quick tutorial" introduces the general idea of a call and explains the most common cases. It does not explain or illustrate all cases. For additional details and/or examples, refer to the links in the "MORE INFO" box.
In the case of parallel right-hand waves, every dancer will have moved one spot around the square in a clockwise direction. (In the case of parallel left-hand waves, they will all move one spot in a counter-clockwise direction.)
The "rolling" action for the three dancers who aren't in-facing ends is similar to a Run. Each of these dancers independently identifies the direction to move based on the location of the dancer who is leaving the line, and in one smooth motion starts turning and moving in that direction, stopping when they have moved over one spot and turned around halfway.