Do the anything call; Very Centers Trade; Center 4 Cast Off 3/4.
Notes:
- 
anything Chain Thru is the same as Finish Diamond Chain Thru
- 
The Cast Off 3/4 can be either an Arm Turn or a 'Push' Cast.
- 
If the anything call is a Triangle or Diamond Circulate,
    the word 'Circulate' is conventionally omitted.  E.g.,  
- 
Some callers use Chain Thru from formations such as
    Parallel Lines and want all the Centers to Trade; and all to
    Cast Off 3/4.
    We believe this is an invalid usage of Chain Thru since it can be
    ambiguous in several situations.  For example, from a Tidal Wave, does
    the caller want the Very Centers to Trade & then the Center 4 to Cast
    Off 3/4, or does the caller want each side to do a Centers
    Trade & all Cast Off 3/4?  Also, if Chain Thru is
    allowed to mean each side Centers Trade followed by all Cast Off 3/4,
    then from Twin Diamonds a Chain Thru could be
    interpreted as Centers of each Diamond Trade (since they are Centers
    of their 4-dancer formation), followed by confusion, since there is no
    adjacent dancer within their 4-dancer formation with whom to Cast Off 3/4.
Diamond Chain Thru [A2] (Deuce Williams 1972):
 From Twin Diamonds.
  Diamond Circulate; Very Centers Trade; Center 4 Cast Off 3/4.
  Usually ends in Parallel Lines.
At C3A there is an additional (unrelated) use of the phrase 'Chain Thru':