The principle of the installation is to create a visual illusion, according to which the surface is static just like the courtyard which surrounds it. Yet, when the visitor ventures to walk to the fault, it becomes unstable; the medium of the «surface» proposes a reading of the courtyard as «the pond». The metaphor continues in the fluid and unstable properties of the surface, which call back that the at first sight dense organization and the complex relaying on a fragile equilibre that it is easy to come to disturb.