The Fly, released in 2005 and discontinued in 2009, was a customizable pen that is intended to assist children with schoolwork. There are several bundled and add-on applications available, including a notepad, calculator, language and writing assistant, and educational games; many of these require the use of a small cartridge that can be inserted into a port built into the rear of the pen. The Fly only works on its own proprietary digital paper, which is lightly printed with a pattern of dots to provide positioning information to the pen via a tiny infrared camera. The ink tip itself can be retracted into the body of the pen when no physical notes are desired.
Many critics of the computer have pointed out the length of time required for the pen to correctly recognise input from the user. Also, some have criticized the lack of a screen, since audio feedback and lights are the only way to get a response from the devices.
