  Aim of this work was to test the idea of J.-Y.Ollitrault about the parallel
squeeze-out type of transversal flow in mid-rapidity region. For this purpose
we have performed a computer simulation of the expanding pion gas created in
non-central Pb-Pb 158GeV/n collisions. A squeeze-out type of asymmetry parallel
to impact parameter in azimuthal distribution of pions is found and studied.
The asymmetry is explained as a consequence of geometry of non-central
collisions and the rescattering process.
