Substitute character actions than the last one can also be undone by pressing multiple times. was one of a handful of keyboard sequences chosen by the program designers at Xerox PARC to control text editing. Presumably these particular keystrokes were chosen because of their location on a standard QWERTY keyboard, since the Z (undo), X (cut), C (copy), and V (paste) keys are located together at the left end of the bottom row of the standard QWERTY keyboard. Substitute character A substitute character (␚) is a control character that is used in the place of a character that is recognized to be
Optimus Maximus keyboard when the user presses the shift key, the pictures would change to upper-case versions. It would also make switching between different keyboard layouts (such as English and Cyrillic) rapid, and could make the switch to alternative layouts such as Dvorak easier for people who only have a QWERTY keyboard with no possibility of rearranging the keys. To demonstrate this concept, there are computer renderings showing example layouts for "Quake III Arena" and Adobe Photoshop. A patent application filed on March 13, 2007 suggests that Apple Inc. may be working on a similar dynamically changeable organic light-emitting diode (OLED) keyboard. Art.