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
Keyboard layout The visual layout of any keyboard can also be changed by simply replacing its keys or attaching labels to them, such as to change an English-language keyboard from the common QWERTY to the Dvorak layout, although for touch typists, the placement of the tactile bumps on the home keys is of more practical importance than that of the visual markings. In the past, complex software that mapped many non-standard functions to the keys (such as a flight simulator) would be shipped with a "keyboard overlay", a large sheet of paper with pre-cut holes matching the key layout of a particular