  The dynamics of wire frame particles in concentrated suspension are studied
by means of a 2D model and compared to those of rod-like particles. The wire
frames have bent or branched structures constructed from infinitely thin rigid
rods. In the model, a particle is surrounded by diffusing points that it cannot
cross. We derive a formal expression for the mean squared displacement (MSD)
and, by using a self-consistent approximation, we find markedly different
dynamics for wire frames and rods. For wire frames, there exists a critical
concentration of points above which they become frozen with the long time MSD
reaching a plateau. Rods, on the other hand, always diffuse by reptation. We
also study the rheology through the elastic stress, and more striking
differences are found; the initial magnitude of the stress for wire frames is
much larger than for rods, scaling like the square of the point concentration,
and above the critical concentration, the stress for wire frames appears to
persist indefinitely while for rods it always decays.
