A protozoa Paramecia were "fed" by 5 micm polystyrene microspheres. One of these spheres  was trapped by optical tweezers and served as an inner handle that rotated the whole vacuole (see images a-d). 

Two and three spots were ablated in the polystyrene sphere of diameter 15 micm by UV laser pulse. Due to this asymmetry the sphere rotated when it was trapped in optical tweezers. 

The asymmetric object consisted of three polystyrene microspheres (diameter 1 micm) is placed on the surface. If one of the microshere was trapped by the optical tweezers, the asymmetric scattering of the trapping beam caused rotation of the whole structure.