An image displaying apparatus employs quartz wave plates and displays images of high contrast. The RF module is configured for sending and receiving a wireless signal. Some brackets include multiple pathways for wires so an amount and type of force applied by the bracket can be varied without moving the bracket. The width in the circumferential direction of the top slot is wider than the width in the circumferential direction of the bottom slot, and the width in the circumferential direction of a rotor tooth between adjacent top slots is narrower than the width in the circumferential direction of the rotor tooth between adjacent bottom slots. A drone is initiated in a maintenance environment for checking patch compliance in response to a request to initiate a virtual machine so that patch updates are performed before the virtual machine initiates in an operational environment accessible to operational clients. The second wireless communication device may also receive the data file via a second wireless network interface and send at least the data of the file that have not been properly received over a neighbor device interface.