The preferred absolute stereochemical configuration notation using the R/S, r/s, … stereodescriptors and CIP rules (as in Loong's detailed answer) might be in some cases quite difficult for human chemist to construct or decipher, like in this case.
There's also a non-preferred, but simpler method using cis/trans notation (IUPAC BlueBook 2013 P-93.5.1.2) for cycles with two stereocenters, and r/c/t (reference, cis, trans) notation (for more ring stereocenters), already mentioned by ℵ_ϵ.
P-93.5.1.3 Relative configuration; the stereodescriptors ‘r’, ‘c’, and ‘t’
P-<IP_ADDRESS><PERSON>'s detailed answer) might be in some cases quite difficult for human chemist to construct or decipher, like in this case.
There's also a non-preferred, but simpler method using cis/trans notation (IUPAC BlueBook 2013 P-<IP_ADDRESS>) for cycles with two stereocenters, and r/c/t (reference, cis, trans) notation (for more ring stereocenters), already mentioned by ℵ_ϵ.
P-<IP_ADDRESS> Relative configuration; the stereodescriptors ‘r’, ‘c’, and ‘t’
P-93.5.1.3.1 When one substituent and one hydrogen atom are attached to each of more than two positions of a monocycle, the steric relations of the ligands are expressed by adding ‘r’ (the reference ligand) after the locant of the lowest numbered of these ligands, and ‘c’ for ‘cis’ and ‘t’ for ‘trans’ (as required) followed by a hyphen and the locant of another ligand, thus expressing the relationship to the reference ligand. The relative configuration is expressed by these stereodescriptors. Furthermore, racemates may also be denoted by this method. For preferred IUPAC names, the preferred stereodescriptors are those used in the CIP priority system described in P-91 and P-92, With stereodescriptors such as ‘R’ and ‘S’ to describe absolute configuration and the prefixes ‘rel’ to express relative configuration and ‘rac’ for racemates, as described in P-93.1.3.
The notation consisting of adding ‘r’ (for reference substituent) followed by a hyphen and the locant of the lowest numbered of these substituents and ‘c’ (for cis) and ‘t’ (for trans) (as appropriate) followed by a hyphen and the locant for another substituent, as used in the 1993 Guide to IUPAC Nomenclature of Organic Compounds (ref. 576
2), is no longer recommended.
(…)
P-<IP_ADDRESS>.2 When two different ligands are attached at the same position of a monocycle, then the lowest-numbered ligand named as a suffix is chosen as reference ligand. If none of the ligands is named as a suffix, then that the ligand of the pair of ligands having the lowest number and Which is higher ranking in the Sequence Rule is chosen as a reference ligand. The relationship of the Sequence-Rule-higher ranking at geminally substituted positions, relative to the reference group, is cited as ‘c’ or ‘t’, as required.
(…)
Example 3:
(1R,2R,3s,4S,5S,6s)-1,2,3,4,5,6-hexachlorocyclohexane (PIN)
1r,2c,3c,4t,5t,6t-hexachlorocyclohexane
Explanation: In this compound, different numberings are necessary in accordance with the precedence of ‘R’ ligands and ‘cis’ arrangements for lowest locants (…)
The notation is for relative stereochemical configuration. But, since each of the six structures in your question is achiral as a whole (superimposable with its mirror image, i.e. a meso form), the relative stereochemical configuration completely describes the absolute configuration as well. 576