  At temperatures well above the transition, QCD admits a thermally reduced
version in 3D, which reproduces the long distance physics. We analyze the phase
diagram, point out the relevance of Z(3) symmetry in the location of the
transition and suggest a way out to reconcile this with the data. Related to
this symmetry is the existence of an observable, the Z(N) wall, or rather its
3D version, and discuss some of its advantages over other observables.
