  We present a new centimeter polarimetric VLBI image of the BL Lac object
0735+178. This source exhibits one of the most pronounced curvatures observed
in jets of AGNs, with two sharp apparent bends of 90 degrees within the inner 2
milliarcseconds from the core. Through the analysis of the data gathered over
the past decades we study whether this curvature is produced by precession of
the jet with ejection of ballistic components, or a precession in such a way
that components' velocity vector are always parallel to the jet axis. These
possibilities are also studied by comparison with 3D hydrodynamic relativistic
simulations of precessing jets.
