From parallel waves: Do the first three parts of Spin Chain [and Exchange] the Gears; Turn the star 1/2 [instead of 3/4], Infacers walks straight ahead to become the #1 dancer in a column; other three dancers in the star follow that leader to form a column. Same person who would be the leader in an Exchange is the leader here. Right-hand waves give left-hand columns and vice versa.