Truck
'Position' in terms of this definition refers to a spot that
could be occupied by a dancer. Within a 2 x 4 there are eight positions.
A Squared Set, Butterfly, or "O" is a 16-Matrix (4 x 4) formation, and
one position refers to an adjacent spot within that rectangular grid.
You could get the impression that Truck has to be done WITHIN the
original matrix. As I understand it, Truck is a Space invader and can therefore
increase/decrease the matrix the formation is mapped on.
