A2io is the companion application to the "A2io" Bluetooth adapter, which is a hardware device for Apple II vintage computers. The A2io application allows the user to interact with the Apple II using touch & motion control, as well as wireless controllers that are paired with the iOS device. The A2io application includes a virtual "paddle" controller, and drawing tablet for use with legacy Apple II drawing software. The game controller interface provides calibration adjustments, and visual feedback while using a paired Bluetooth controller with an Apple II computer.