In contrast to the group of integers above, where the order of the operation is immaterial, it does matter in ⁠ D 4 ⁠, as, for example, f h ∘ ∘ r 1 = f c but ⁠ r 1 ∘ ∘ f h = f d ⁠. In other words, D 4 is not abelian.