OFFSET
1,3
COMMENTS
It would be nice to have a definition of "polypon"! - N. J. A. Sloane, May 09 2007
By looking at the Clarke pictures, I guess that the unit element is a triangle with internal angles of 120 degrees and two of 30 degrees. The polypons are connected, nonoverlapping assemblies of these, where connectivity is defined via common sides; a common point is not enough. Only non-congruential assemblies are counted, those which cannot be mapped onto each other by rotations, translations or mirrors along a line or point. However, the polypons are not all of these, because some of the free-form assemblies of this kind would need placement of the unit that violates the format by the grid. (The first case where this happens is with assemblies of 3 units: the picture shows 2 examples with assemblies of 3 units, but I can imagine at least 1 more where the unit would need to hide/cover one of the grid's edges.) - R. J. Mathar, Dec 10 2007
REFERENCES
Computed by Brendan Owen.
LINKS
Andrew Clarke, Other Polyforms
CROSSREFS
KEYWORD
dead
AUTHOR
N. J. A. Sloane, Nov 04 2000
EXTENSIONS
Link updated by William Rex Marshall, Dec 16 2009
STATUS
approved