A rotor unit includes a plurality of rotating bodies arranged along a central axis. At least some components have mechanical coupling elements that enable the configuration of the apparatus to be varied by changing at least one of the relative orientation and position of those components or subsystems. The back frame carries the light source and the light homogenization mechanism, and the light homogenization mechanism guides light from the light source into the display panel. Then, the cross-linked polymeric composite undergoes a simple-sheared process and turns into a polymeric composite with a strain more than 1%.