Mirror writing is formed by writing in the direction that is the reverse of the natural way for a given language, such that the result is the mirror image of normal writing: it appears normal when it is reflected in a mirror. It is sometimes used as an extremely primitive form of cipher. The most common modern usage of mirror writing can be found on the front of ambulances, where the word "AMBULANCE" is often written in very large mirrored text, so that drivers see the word the right way around in their rear-view mirror.

Research suggests that the ability to do mirror writing^{[clarification needed]} is probably inherited and caused by atypical language organization in the brain. It is not known how many people in the population inherit the ability of mirror writing (an informal Australian newspaper experiment identified 10 true mirror-writers in a readership of 65,000). Half of the children of people with the ability inherit it. There are more left-handed mirror writers than right-handed ones, probably because left-handed people tend to have atypical language centers in their brain. 15% of left-handed people have the language centres in both halves of their brain.^{[citation needed]} The cerebral cortex (thin layer of dense brain cells covering the whole brain) and motor homunculus (relates to voluntary movement) are affected by this causing them to be able to read and write backwards quite naturally.^{[citation needed]}

Leonardo di ser Piero da Vinci (Italian pronunciation: [leoˈnardo da ˈvintʃi]  pronunciation (help·info); April 15, 1452 – May 2, 1519, Old Style) was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist, and writer whose genius, perhaps more than that of any other figure, epitomized the Renaissance humanist ideal. Leonardo has often been described as the archetype of the Renaissance Man, a man of "unquenchable curiosity" and "feverishly inventive imagination". He is widely considered to be one of the greatest painters of all time and perhaps the most diversely talented person ever to have lived. According to art historian Helen Gardner, the scope and depth of his interests were without precedent and "his mind and personality seem to us superhuman, the man himself mysterious and remote". Marco Rosci points out, however, that while there is much speculation about Leonardo, his vision of the world is essentially logical rather than mysterious, and that the empirical methods he employed were unusual for his time.