  The well-known Bean critical state equations in general are not sufficient to
describe the critical state of type-II superconductors when the sample shape is
not symmetric. We show how one can find the critical state in superconductors
of arbitrary shape. Analyzing a simple example of nonsymmetry, we demonstrate
that in the general case, a perturbation of the current distribution in the
critical state propagates into the sample smoothly in a diffusive way. This is
in contrast to the usual Bean critical state where the current distribution
changes abruptly at a narrow front.
