In the recursive elaboration of a flexagon, a single n-gon is replaced by a counterrotating package of (n - 1) n-gons. If the n-gon is not regular, a single substitution will produce different plans according to the edge involved. The ultimate flexagon should look and act the same irrespective of the place where the substitution is made, but the plans from which they are folded may overlap differently, requiring artistic anjustments in the actual frieze which will be laid out.