  We calculate the temperature and polarization patterns generated in
anisotropic cosmological models drawn from the Bianchi classification. We show
that localized features in the temperature pattern, perhaps similar to the cold
spot observed in the Wilkinson Microwave Anisotropy Probe (WMAP) data, can be
generated in models with negative spatial curvature, i.e. Bianchi types V and
VII$_{h}$. Both these models also generate coherent polarization patterns. In
Bianchi VII$_h$, however, rotation of the polarization angle as light
propagates along geodesics can convert E modes into B modes but in Bianchi V
this is not necessarily the case. It is in principle possible, therefore, to
generate localized temperature features without violating existing
observational constraints on the odd-parity component of the polarization of
the cosmic microwave background.
