  We construct a black hole initial data for the Einstein equations with
prescribed scalar curvature, or more precisely a piece of initial data
contained inside the black hole. The constraints translate into a parabolic
equation, with radius as "time" variable, on a metric component u that
undergoes blow up. The metric itself is regular up to and including the surface
at blow up radius, which is a minimal surface. By applying equivariant
bifurcation theory on a self similarly rescaled equation, we show the existence
of blow up profiles that are not O(3) symmetric - or anisotropic - although the
curvature was isotropically prescribed.
