Illustration of the basis tensors of 𝕍₂₂₂ versus those of 𝕍₍₂₂₂₎. Top: without the symmetry requirement between groups (indicated by usage of different symbols for each group) there are five basis tensors. Bottom: With the additional symmetry requirement between groups (indicated by usage of the same symbol for each group), since the latter three tensors of 𝕍₂₂₂ get all united to a single symmetrised term (bottom).