  The recent solution of the Mandelstam constraints for SU(2) is reviewed. This
enables the subspace of physical configurations of an SU(2) pure gauge theory
on the lattice (introduced solely to regulate the number of fields) with 3N
physical degrees of freedom to be fully described in terms of 3N
gauge-invariant continuous loop variables and N-1 gauge-invariant discrete +/-1
variables. The conceptual simplicity of the solution and the essential role of
the discrete variables are emphasized. (Talk presented at QCD '94, Montpellier,
France, 7-13 July 1994.)
