The Arm Turn 1/2 that is being replaced does not have to be the first part of the call: it just has to be the first Arm Turn 1/2 within the given call. For example (from Facing Lines), a Yo-Yo Square Chain Thru is a Right Pull By, 1/4 In & Left Touch; Left Arm Turn 3/4; Centers Trade; Left Turn Thru. EN: 20

Historically, Yo-Yo was not a CONCEPT, but several different calls which used the words Yo-Yo and the Arm Turn 3/4 idea. This was not only messy, but confusing to the dancers, since calls were named Relay The Yo-Yo (Yo-Yo Relay The Top); Alter The Yo-Yo (Yo-Yo Alter The Wave); Change The Yo-Yo (Yo-Yo Change The Wave); Reverse The Yo-Yo (Yo-Yo Reverse The Top); etc. Each call had to be separately memorized. EN: 30