  Although the cubic T^3 "small universe" has been ruled out by COBE/DMR
results as an interesting cosmological model, we still have the possibility of
living in a universe with a more anisotropic topology such as a rectangular T^3
"small universe" with one or two of its dimensions significantly smaller than
the present horizon (which we refer to as T^1- and T^2-models, respectively).
In order to rule out these anisotropic topologies as well, we apply a new data
analysis method that searches for the specific kind of symmetries that these
models should produce. We find that the 4 year COBE/DMR data set a lower limit
on the smallest cell size for T^1- and T^2-models of 3000h^{-1} Mpc, at 95%
confidence, for a scale invariant power spectrum (n=1). These results imply
that ALL toroidal universes (cubes and rectangles) are ruled out as interesting
cosmological models.
