From Parallel Columns of {n},
where n is greater than or equal to 3.
The First n dancers (where n corresponds to the given
fraction, see first note below) as a unit Trail Off to end in
Concentric Columns of n as the remaining dancers, using Circulates,
move forward to form a compact formation.
Notes:

From Parallel Columns of 4, n=1 for 1/4;
2 for 1/2; 3 for 3/4; or 4 (full) if no fraction is given.

From Parallel Columns of 3, n=1 for 1/3;
2 for 2/3; or 3 (full) if no fraction is given.

On a full Cross Invert The Column, everyone does the
Trail Off movement but must also slide together upon completion of the call
to form adjacent Columns. Do not slide together if call is
fractionalized (e.g., 3/4 Cross Invert The Column ends
in an "H").
 before Cross Invert The Column  
 
 
 
 after 1/4   after 1/2   after 3/4   (done) 

Variation:Magic Cross Invert The Column fraction [C2V].
See also Invert The Column (fraction) [C2].