  We consider here quasiperiodic potentials on the plane, which can serve as a
"transitional link" between ordered (periodic) and chaotic (random) potentials.
As can be shown, in almost any family of quasiperiodic potentials depending on
a certain set of parameters, it is possible to distinguish a set (in the
parameter space) where, according to a certain criterion, potentials with
features of ordered potentials arise, and a set where we have potentials with
features of random potentials. These sets complement each other in the complete
parameter space, and each of them has its own specific structure. The
difference between "ordered" and "chaotic" potentials will manifest itself, in
particular, in the transport properties at different energies, which we
consider here in relation to systems of ultracold atoms. It should be noted
here that the transport properties of particles in the considered potentials
can be accompanied by the phenomena of "partial integrability" inherent in
two-dimensional Hamiltonian systems.
