Provided are a method, system, and article of manufacture for creating playback definitions indicating segments of media content from multiple content files to render. An upper portion is integrally attached to the support structure, where the upper portion is formed of a flexible material defining opposing portions. A differential gear interconnects the suspension rotor and adjustment rotor and is configured to transmit to the adjustment rotor the same speed of rotation that is imparted to the suspension rotor by a main rotation drive unless an adjustment drive imparts differential rotation to the adjustment rotor.