  Schr\"odinger equation for an electron confined to a two-dimensional strip is
considered in the presence of homogeneous orthogonal magnetic field. Since the
system has edges, the eigenvalue problem is supplied by the boundary conditions
(BC) aimed in preventing the leakage of matter away across the edges. In the
case of spinless electrons the Dirichlet and Neumann BC are considered. The
Dirichlet BC result in the existence of charge carrying edge states. For the
Neumann BC each separate edge comprises two counterflow sub-currents which
precisely cancel out each other provided the system is populated by electrons
up to certain Fermi level. Cancelation of electric current is a good starting
point for developing the spin-effects. In this scope we reconsider the problem
for a spinning electron with Rashba coupling. The Neumann BC are replaced by
Robin BC. Again, the two counterflow electric sub-currents cancel out each
other for a separate edge, while the spin current survives thus modeling what
is known as pure spin current -- spin flow without charge flow.
