  It has been proposed that intermittent weak links between spontaneously
broken symmetry systems can give rise to a novel type of time crystal. Here a
practical construction is analyzed in greater detail. For a film-geometry
Josephson junction, an applied magnetic field in the junction region can
effectively switch on and off the supercurrent. By tuning experimental
parameters, one can possibly let the free energy be arbitrarily close to the
equilibrium without compromising the life time. A parallel construction for
superfluid $^4$He is also proposed.
