A polyare is a polyform obtained from a polyomino by cutting each square cell into two congruent rectangles
parallel to a pair of its sides and retaining one half, so that the remaining halves
are connected along line segments of positive length.
Some joins between cells of the original polyomino
may be lost. An -are
is obtained from a polyomino with
cells.
The first few -ares
are illustrated above. In counting free
-ares, translations, rotations,
and reflections are identified. For one-sided
-ares, only translations
and rotations are identified. The following table gives
the numbers of free and one-sided
-ares for
, 2, ..., 8.