Conveyor system accessories are disclosed, which provide an inexpensive way to stage, stockpile andor sort work pieces and provides easy entry to and exit from a main conveyor. A computer implemented method for balancing a binary search tree includes locating a node in a binary search tree, determining whether a depth of the located node is greater than a threshold, and performing balancing operations. The protective holder prevents inadvertent depression of buttons on such remote controls when the remote control is stored in a pocket or purse. When a toy train passes over the sensor on the track, the entertainment device is activated. Thereafter, the top electrode and free layer are patterned.