When vertex adornments are added in the second stage, the atom type becomes significant so only the identity mapping and the reflection through the oxygen atom are automorphisms. In the final stage, edge adornments are added but in this example the automorphism group is not further reduced since the reflection through the oxygen atom preserves both atom type and bond multiplicity. Note how the automorphism groups in the second and third stages are subgroups of the automorphism groups in the previous stages.