Cyclic symmetry in three dimensions

In three dimensional geometry, there are four infinite series of point groups in three dimensions (n≥1) with n-fold rotational or reflectional symmetry about one axis (by an angle of 360°/n) that does not change the object.

They are the finite symmetry groups on a cone.

For n = ∞ they correspond to four frieze groups.

The terms horizontal (h) and vertical (v) imply the existence and direction of reflections with respect to a vertical axis of symmetry.

C2h, [2,2+] (2*) and C2v, [2], (*22) of order 4 are two of the three 3D symmetry group types with the Klein four-group as abstract group.