Based on Pitteri and Zanzotto (1996b),1 and on the results of chapters 5 and 8, here we give a description of all the transformation twins that are possible in simple lattices. To do so we check all the rank-1 connections between any pair of variants in the same variant structure in the wt-nbhds. As in chapter 5, we consider wt-nbhds of reference bases whose symmetry is maximal, that is, bases of any of the three cubic types, or of the hexagonal type. The cases involving a reference lattice with nonmaximal symmetry can be derived from these.