It’s practically a rite of passage for every child to create his or her own secret language, often scrawled onto sheets of notebook paper, passed in hallways and behind the backs of teachers. The use of symbols and codes is common among marginalized groups of society, who develop a need to communicate secretly with their brethren. In Chengdu, the capital of China’s Sichuan province, police recently released a list of seventeen secret symbols used by thieves. As a coded means of communication, vandals use chalk or spray paint to mark buildings and warn fellow criminals. The pictographs are simple and geometric; a sideways ladder indicates a dangerous area to avoid, while a perfect diamond translates to, “No one lives here.”
One of the most well known studies of modern-day secret symbols comes from homeless travelers who wandered the US during the Great Depression, creating a vast set of pictographs that are still documented and translated today (see above image). As men and women traveled with changing harvests, looking for work on farms, they scrawled symbols next to dwellings and towns, informing others of the road ahead. For example, a house with a large “T” written on the nearby sidewalk indicates that the family within will give a traveler a meal in exchange for work. If the “T” were accompanied by a simple drawing of a plump cat, it meant that the housewife was generous and kind.
If you look around, we are surrounded by secret codes. Not meant for general comprehension, yet symbols come in the form of graffiti and altered signs, adorning the walls and streets of public areas. The image above, taken during a rainy walk in New York City, is presumably the scrawling of a city employee, making note of a sewage or cable system below the pavement. The yellow markings are nevertheless a code, meant for the benefit of someone else’s daily life. So keep your eyes open — what may look like incomprehensible chicken scratch might be an important message, protecting and informing a secretive member of society.