Control-C else, typically returning control to the user. Ctrl-C was one of a handful of keyboard sequences chosen by the program designers at Xerox PARC to control text editing, with Ctrl-Z (Undo), Ctrl-X (Cut), Ctrl-V (Paste), and Ctrl-P (Print). The first four letters are all located together at the left end of the bottom row of the standard QWERTY keyboard, and P towards the upper right. The equivalent key combination on Macintosh computers is Command-C. Control-C as an abort command was popularized by TOPS-20 and TOPS-10 and adopted by other systems including Unix. It was also adopted by Digital Equipment operating
Dvorak Simplified Keyboard closed out. Apple also includes a Dvorak variant they call "Dvorak – Qwerty ⌘". With this layout, the keyboard temporarily becomes QWERTY when the Command (⌘/Apple) key is held down. By keeping familiar keyboard shortcuts like "close" or "copy" on the same keys as ordinary QWERTY, this lets some people use their well-practiced muscle memory and may make the transition easier. Mac OS and subsequently Mac OS X allow additional "on-the-fly" switching between layouts: a menu-bar icon (by default, a national flag that matches the current language, a 'DV' represents Dvorak and a 'DQ' represents Dvorak – Qwerty ⌘) brings