negative, things are shifted to the left.
FROM     --- The left point of the region to move, inclusive.
TO       --- The right point of the region to move, exclusive.
ADJUST   --- Whether to adjust the fill pointer and the array bounds. The array is only
             adjusted if N is positive and the range of TO+N would exceed the ARRAY length,
             or if N is negative and TO equals the length of the ARRAY
FILL     --- If provided, empty spaces created by the move will be filled with this element.
C