Offset concepts (Parallelogram, Offset Lines) and Phantom concepts
(Split Phantom Lines, Split Phantom Boxes) require special care, and
do not work well together in all cases. This is because Offset
concepts require a rigorously well-defined notion of the shape of the
starting and ending formations, and Phantom concepts can conceal any
offset by making "real" spots and "phantom" spots
indistinguishable.
In fact, it is essentially meaningless (except in "gimmick"
sequences) to nest a Phantom concept followed by an Offset concept.
That is, "Triple Box Parallelogram" is meaningless. Whatever the
actual occupation of the matrix, Triple Boxes turns it into a 2x6 in
which all spots are equally important. The Parallelogram concept
can't do anything with the result. Therefore, the best we can do in
terms of combining the concepts is to use an Offset concept first,
followed by a Phantom concept.
For Offset concepts to deal with shape-changing calls, they use a notion
of "offset percentage" or "offset fraction", which is the fraction of
one of the offset sub-setups that overhangs and does not line up with the other.
For normal parallelograms or offset lines, it is 50%.
\sxhBBBs{g1s,.+.,b1n,.+.,g4s,b2s}
\sxhBBVs{g1s,.+.,b1n,.+.,g4s,.+.,b4n}
50% offset (1/2 of each 1x4, or 2 people, overhang)
75% offset
The rule for doing an offset concept is to do it as though the "shear
direction" and offset percent were noted, the offset removed, the
call executed, and the same percent offset re-imposed. If the offset
is not an integer number of people in the new formation, or is
otherwise not sensible, the call is illegal. (An exception to this is
the "50% offset diamond" obtained by having the centers Hinge from a
parallelogram. It is accepted that this is a meaningful setup.)
Phantom concepts can involve what is generally considered to be a
change in the formation size as phantoms are placed at the start of
the call and removed at the end. This can lead to serious problems in
measuring offset percentages.
One case that is easy to deal with and fairly commonly used is the
case in which the placement of new phantoms is perpendicular to the
direction of the offset. The phantoms are placed directly outboard of
the real people.
\sxhBBBs{...,g2e,...,b2e,b3w,g1e}
\sxvJJJJs{.+.,.+.,.+.,.+.,g2e,b2e,g1e,b1e}
before Parallelogram Split Phantom Columns Transfer the Column
place phantoms
\sxvJJJJs{.+.,b2s,.+.,g2s,.+.,g1s,.+.,b1s}
\syhBBBBs{.+.,.+.,g2s,b1s,.+.,.+.,b2s,g1s}
do the call, maintain 50% offset
actual result
If the call is a shape-changer, the percent offset rule still works:
\sxhBBBs{...,g2e,...,b2e,b3w,g1e}
\sxvJJJJs{.+.,.+.,.+.,.+.,g2e,b2e,g1e,b1e}
before Parallelogram Split Phantom Columns Settle Back
place phantoms
\syvPPPPs{g1n,g2n,b1n,b2n,.+.,.+.,.+.,.+.}
\syvlines{g1n,g2n,b1n,b2n}
do the call, maintain 50% offset
actual result
\sxvBBBs{...,...,g3s,b3n,g4s,b4n}
\sxhPPPPs{.+.,.+.,.+.,.+.,g4s,g3s,b4n,b3n}
before Offset Waves Split Phantom Boxes Recycle
place phantoms
\syhJJJJs{.+.,b2n,.+.,b1n,.+.,g2n,.+.,g1n}
\syhBBBBs{b2n,.+.,g2n,.+.,.+.,g3s,.+.,b3s}
do the call, maintain 50% offset
actual result
Of course, concepts like Split Phantom Columns don't always start with the real people in the "inboard" position;
they can be anywhere in the matrix. The rule is that, when offsets are involved, the locations of the real people
must be able to identify unambiguously which way the offset goes.
\sxvJJJJs{g2e,b2e,g1e,b1e,.+.,.+.,.+.,.+.}
\sxvJJJJs{.+.,g1n,.+.,b1n,.+.,b2n,.+.,g2n}
\syhBBBBs{.+.,.+.,b1n,g2n,.+.,.+.,g1n,b2n}
before Parallelogram Split Phantom Columns Transfer the Column
do the call, maintain 50% offset
final result
The direction of the offset was clear, even though the people were not in their "inboard" positions.
In order for this to work, the percentage offset must be determined by the concept itself; it isn't possible in
general to determine both the direction and the percentage offset from looking at the occupied spots.
For Parallelogram Split Phantom Columns/Lines/Waves and Offset Split Phantom boxes,
the offset is always 50%.
\sxvJJJJs{g2s,b2s,g1n,b1n,.+.,.+.,.+.,.+.}
\sxvlines{b1s,g2s,b4n,g3n}
before Parallelogram Split Phantom lines Trade Circulate
after
When the direction in which the phantoms are placed is parallel to the
offset direction, one needs to be especially careful. The individual subsetups are sheared. Once again, the
amount of offset must be knowable from the concept itself. The only known workable cases of this use an offset
of 100% within each subsetup. As before, the direction of the offset must be able to be determined
unambiguously from the locations of the people.
\syhBBBBs{...,...,b4w,.+.,g3w,.+.,g2w,b1e}
\syhBBBBs{...,...,.+.,g4w,.+.,g1w,b1w,b2w}
before Offset Triple Waves Switch the Wave; each line is sheared by one matrix position, or 100%
after
The Offset Triple Boxes/Columns/Lines/Waves concepts are discussed in more detail in
Previous
Up
Next