The AB3 ETP-3 E′-mode configuration space features seven, at least planar, polytope genera as shown in Fig. with details shown in Table . The hyperplanes at the boundaries of the six triangular regions of the AB3 ETP-3 E′-mode 𝒞 ̅ 3E ′ configuration space indicate where polytopal rearrangements cannot traverse. Consequently, these six chambers are ABn-stereoisomerically disconnected.