The idea has been suggested earlier by others, but was stressed again recently by Coimbra (2013): some concentric circles present in rock art may represent the depiction of enclosures. In this case, the rock 132 from Fratel (middle Tagus river, central Portugal) really resembles a ditched enclosure with a gate with its “crab pincers”, reminding Perdigões outer gates, Xancra or many others from France.
(image taken from F. Coimbra, 2013, Ruptejo. Arqueologia rupestre da bacia do Tejo)
Gate 2 of Perdigões
Enclosure of Chez-Reine (France)
As I put it recently, a same general idea can be expressed in an architectonic design, in a decoration of a pot, in pattern of a textile, in a motive of an art composition. Does this particular association of the motive on rock 132 to an enclosure depiction makes sense? Why not?