One interesting thing is the complexity of atomic shuffling ([Yi 05]). Because of the
double lattice system of hcp structure, the translation of four atomic layers is needed to
complete the tensile twinning process in case of Mg. The atoms in second or third layers can
only have the small amount of translation, so-called shuffling. The parameter q in Table 2.3
indicates the required atomic spacing for twinning. A schematic image of atom translation in
tensile twinning is shown in Figure 4.23