A rosette C8
The principal rosette on the facade of the Duomo in Gemona: at first sight, it seems to have a dihedral symmetry; instead, the symmetry is cyclic of type C8. If we ignore a certain detail (which one?), we could say that it is a cyclic symmetry of type C16.
The image belongs to the sections...:
8. (C8) (Symmetry)
Buildings (Anthology of images)
Higher order (Symmetry)