  Evolution of anisotropy in momentum and coordinate space of the parton system
produced in relativistic heavy-ion collisions is discussed within the
free-streaming approximation. The momentum distribution evolves from the
prolate shape - elongated along the beam - to the oblate one - squeezed along
the beam. At the same time the eccentricity in the coordinate space, which
occurs at finite values of impact parameter, decreases. It is argued that the
parton system reaches local thermodynamic equilibrium before the momentum
distribution becomes oblate.
