A very large extra dimension may contain many localized branes. We discuss
the possibility to formulate such models as a spin system where each spin
indicates the supersymmetry direction preserved by the corresponding brane. In
the evolution of the universe, the extra dimensions might have ended into a
vacuum made of patches with different orientation of the spins, responsible for
the observed breaking of supersymmetry. We discuss the limit where the
separation of these patches is by very thin defects described as localization
of gravitino masses.Comment: 15 pages, no figure. Typos corrected. References added. Version
accepted for publication