Mirror writing refers to the process of writing language in the reverse. When the reverse writing is viewed in a mirror, it appears normal. This writing style has been used throughout history for mystical writing and ciphers, and it is used currently to ensure drivers can read important words when seen in the mirrors of a car. It is also sometimes used in a form of typographical art known as an ambigram.
The ability to compose mirror text is thought to be inherited, as researchers have found it to be linked to specific brain functions. It is also thought to be relatively rare, although no one really knows how many people can do it. Most mirror writing is performed by people who are left handed; this is thought to be due to the fact that left handed individuals have language areas in the brain on both the left and right side, while right handed individuals have language areas on only one side of the brain.
When learning to write, some children actually write in mirror image naturally, beginning on the left side of the page and moving towards the right. This type of writing is normally corrected. There are also some forms of dyslexia in which individuals see writing in the mirror image; this is much more difficult to correct. Mirror writing has also been linked to some medical conditions, including some cases of brain damage.
This style of writing has been found throughout history. During the 18th and 19th century, calligraphy was often writing in mirror images, as the writings were thought to be of mystical origins. Leonardo da Vinci, one of the most famous mirror writers, wrote many of his personal notes this way. Mirror writing has been used in cryptology, or code writing, as a very basic type of cipher. The code is written in reverse, and can easily be read when held up to a mirror.
Larger mirrored text is frequently used on emergency vehicles and some signs for automobiles. Mirror writing is used so that drivers will see the word in the proper orientation when viewing it through the rear view mirror.
A related form to mirror writing is an ambigram. The ambigram is a design or work off art that can be read when viewed from a different orientation. When calligraphy is used, the ambigram typically contains two different words, one found when viewing the work normally and then another word when the image is held up to a mirror. The mirror style is only one of several different types of ambigram.