  It is shown that nonsymmetric microobjects orient while settling under
gravity in a viscous fluid. To analyze this process, a simple shape is chosen:
a non-deformable `chain'. The chain consists of two straight arms, made of
touching solid spheres. In the absence of external torques, the spheres are
free to spin along the arms. The motion of the chain is evaluated by solving
the Stokes equations with the use of the multipole method. It is demonstrated
that the spinning beads speed up sedimentation by a small amount, and increase
the orientation rate significantly in comparison to the corresponding rigid
chain. It is shown that chains orient towards the V-shaped stable stationary
configuration. In contrast, rods and star-shaped microobjects do not rotate.
The hydrodynamic orienting is relevant for efficient swimming of non-symmetric
microobjects, and for sedimenting suspensions.
