With the Michael one "MarkCurveMatchingEnds"
As I suppose the polygon has only one Start End...(itself alone don't works (as not considered as a curve ? ) )

(here 5 simple curves and 1 polyline)



so 5 connections if matching! :)

http://moiscript.weebly.com/uploads/3/9/3/8/3938813/only_1_point.3dm