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
Dvorak Simplified Keyboard change. The Dvorak layout is often used in economics textbooks as a standard example of network effects, though this method has been criticized. Most keyboards are based on QWERTY patterns, despite the availability of other keyboard patterns, including the Dvorak. Although DSK is implemented in many languages other than English, there are still potential issues. Every Dvorak implementation for other languages has the same difficulties as for Roman characters. However, other (occidental) language orthographies can have other typing needs for optimization (many are very different from English). Because Dvorak Simplified Keyboard was optimized for the statistical distribution of letters of