A method and apparatus is disclosed for simultaneously creating a pair of stacks of nested sinuous spring strips. A pair of differential bushings are located in the housing on opposite sides of the drive gear. The visualization system can specifically target information and action requests to different classes of manufacturing personnel such as operators and engineers. The device may also monitor a distance traveled by the user. For rear wheel drive configurations, the non-regenerative brakes can be applied to just one front axle wheel on the outside of a turn.