We construct an exactly solvable commuting projector model for a 4 + 1 dimensional Z 2 symmetry-protected topological phase (SPT) which is outside the cohomology classification of SPTs. The model is described by a decorated domain wall construction, with "threefermion" Walker-Wang phases on the domain walls. We describe the anomalous nature of the phase in several ways. One interesting feature is that, in contrast to in-cohomology phases, the effective Z 2 symmetry on a 3 + 1 dimensional boundary cannot be described by a quantum circuit and instead is a nontrivial quantum cellular automaton (QCA). A related property is that a codimension-two defect (for example, the termination of a Z 2 domain wall at a trivial boundary) will carry nontrivial chiral central charge 4 mod 8. We also construct a gapped symmetric topologically-ordered boundary state for our model, which constitutes an anomalous symmetry enriched topological phase outside of the classification of Ref.[1], and define a corresponding anomaly indicator.(⇒) If U acts as a QCA by conjugation, β(X i ) is supported near spin i for a spin Pauli operator X i at i. Hence, since this operator must commute with X j for j far from i, not only is (V z+i ) † V z an operator on the material supported near spin i, it is equal to (V z+i+j ) † V z+j for any j far from i. In words, (V z+i ) † V z depends only on spins near i.Note that U dis acting by conjugation as a QCA is a stronger requirement than just that U mat z acts by conjugation as a QCA as it also imposes locality requirements on the spin degrees of freedom. Heuristically, it means that changing z locally will only change the action of U mat z locally.Following [13], we believe that if one restricts U mat z to just the material degrees of freedom in the domain wall manifold M z , then it is nontrivial, i.e., it cannot be written as a quantum circuit