Non-linear writing

Non-linear writing is a system of writing whose symbols are made up of something other than lines, as distinct from linear writing. It is also a writing composition which does not proceed in a straight-line, step-by-step fashion, such as where an author creates a story's ending before the middle is finished.

Non-linear symbols
Cuneiform is probably the earliest non-linear writing. Its symbols are different-shaped impressions, formed by pressing the sharpened end of a reed stylus into moist clay, not scratching the clay in lines as had been done previously.

Arguably, the symbols of Chinese script might be considered non-linear since they are formed of brush strokes, which are not lines of uniform width. However, the essence of the characters can in fact be rendered by plain lines, so this remains an open question. The same argument applies to Egyptian hieroglyphics and Maya hieroglyphics, which are either painted in great detail or carved into stone.

There are several non-linear adaptations of the Latin alphabet, based upon the principles of simple substitution ciphers. There is a one-to-one correspondence between the original linear symbols and the new non-linear symbols. In the case of the Braille alphabet for the blind, the new symbols consist of raised bumps on the writing substrate, which can be paper, metal, plastic or Louis Braille's original leather. In the case of maritime signal flags, the symbols are individual flags with varied coloration.

The pattern of encoded magnetic traces used in modern computers is also a substitution cipher for traditional linear alphabets. Although such magnetic traces may be evanescent, they are still permanent enough to allow works to be copyrighted. Two early encoding schemes were the ASCII and the EBCDIC, and today there are dozens of variations.

There are also impermanent substitution ciphers of the Latin alphabet, including: If writing is defined as a permanent means of recording information, then these systems do not qualify, since the symbols disappear as soon as they are used.
 * Morse Code,
 * the alphabetic component of the various signed languages;
 * two varieties of semaphore:
 * one involving flags waved according to specific patterns;
 * one involving stationary bars held at different prescribed angles.