To define this ensemble of elements characteristic to the urban culture under question, we might use the term ?opening?. But this does not exactly cover all the aspects related to the controlled ambiguity and complexity, to the inter-penetration and transition between spaces. In this sense, we should probably use the term ?transparency?. Not so much in the literal sense of the word (although this quality of the closings essentially contributes to the overall image), but rather in the sense of virtual transparency: a particular quality of the way the forms are organised that permits the simultaneous perception of different spatial layers. This distinction, and the virtual transparency as criterion for spatial analysis, is attributed to Colin Rowe and Robert Slutzky (1992)[i]; and starts from an analogy with real transparent objects, that are perceived as such, and at the same time allow us to perceive the objects situated behind them. It?s just that, in this sense, we would talk of a ?reciprocal? transparency, of a capacity of some figures to intersect without annulling themselves from a visual point of view. ?The fluctuation? of the elements perceived as simultaneously belonging to systems of different arrangements, gives to a work of art (or, in our case, to an urban image) an ambivalent sense, a structural ambiguity that still presupposes control and the possibility of multiple yet coherent readings.

The pertinence of the concept of virtual transparency, based on ambiguity and overlapping could obviously appear as confusing. Usually, transparency is also used for characterising whatever is clear, understandable, not dissimulated. But, it is precisely this connotation of integrity of objects that risks creating confusion as to the characteristics of an architectural or urban space. The term ?opening? is usually used to describe a certain ensemble of qualities specific to Bucharest?s urban space before the transformations from the past 50 years. But, for example, both the traditional and modern architecture of the Dutch houses, with their interior spaces perfectly visible from the exterior, is characterised as transparent. It is however a transparency created by a linear limit between two spatial realms ? the interior and the exterior of the building that remain perfectly delimited. The modernist town planning, too is generically called ?open town planning?. The buildings conceived of as isolated objects are located independently of the network of circulation, in a total space, of a public nature. Only the access and distribution halls and the individual balconies mediate between this almost homogenous space and the interior spaces of the flats.

In order to describe an opening that actually manifests itself through various intermediary spaces, through complex articulations between the private and the public space, the term of virtual transparency, as defined before, seems to have a certain relevance, due to the spatial fluidity and ambiguity that it suggests.