  A crystallographic bar-joint framework C is shown to be almost periodically
infinitesimally rigid if and only if it is strictly periodically
infinitesimally rigid and the rigid unit mode (RUM) spectrum is a singleton.
Moreover the almost periodic infinitesimal flexes of C are characterised in
terms of a matrix-valued function on the d-torus determined by a full rank
translation symmetry group and an associated motif of joints and bars.
