Patent attributes
Described herein are accessory devices that are configured to both perform accessory functions for electronic devices, as well as output content that is supplemental or complementary to content being output by the electronic devices. The accessory functionality of the accessory devices may be far-ranging and may include reading lights, covers, projectors, universal serial bus (USB) drives, cameras, page-turn buttons, audio jacks, expansion headers, Bluetooth devices, biometric sensors, ambient light sensors, and more. These accessory devices may complement the operation of any number of electronic devices. For instance, an accessory device may both comprise a reading light to illuminate a display of an electronic book (eBook) reader device, as well as a display to display content that has been deemed supplemental to the content being displayed by the eBook reader device.