[Revised version of Fig. 2 of Michels-Clark et al. (2013).] Examples of unique five-layer stacking motifs: layers 1, 2, 3 in solid black from left to right, layer 4 in green, and layer 5 in red. In the actual crystal structure overlapping arms of molecules in neighboring layers sit on top of each other, but they are slightly displaced here for clarity. The symbols above each motif describe the four- and five-layer stacks. The abbreviations bL, bR, e (bent left, bent right, eclipsed) characterize the three possible three-layer stacks. A four-layer stack is defined by two symbols and a five-layer stack by three symbols. Respective transition probabilities from four- to five-layer stackings are given at the bottom of each motif.