Editing Polyabolo (section)

==Combinatorial enumeration==
There are two ways in which a square in a polyabolo can consist of two isosceles right triangles, but polyaboloes are considered equivalent if they have the same boundaries. The number of nonequivalent polyaboloes composed of 1, 2, 3, … triangles is 1, 3, 4, 14, 30, 107, 318, 1116, 3743, … {{OEIS|id=A006074}}.

Polyaboloes that are confined strictly to the plane and cannot be turned over may be termed one-sided. The number of one-sided polyaboloes composed of 1, 2, 3, … triangles is 1, 4, 6, 22, 56, 198, 624, 2182, 7448, … {{OEIS|id=A151519}}.

As for a [[polyomino]], a polyabolo that can be neither turned over nor rotated may be termed fixed. A polyabolo with no symmetries (rotation or reflection) corresponds to 8 distinct fixed polyaboloes.

A [[Simply connected|non-simply connected]] polyabolo is one that has one or more holes in it. The smallest value of ''n'' for which an ''n''-abolo is non-simply connected is 7.