Prison tattoos are those that are created while incarcerated or are designed to look that way. They may convey gang or mafia affiliation, racism or toughness.
Tattooing requires an implement that perforates the skin and ink. As these supplies are not readily available to prisoners, they generally improvise with sharp objects such as paper clips, mechanical pencils, staples or internal parts from machinery. Ink quite often comes from the ink of a pen, though prisoners also use burned styrofoam and melted plastic
The specific meanings of the tattoos vary between groups and individuals. According to BBC.com, Russian prison tattoos carry a lot of meaning. For instance, a bracelet tattoo signifies more than five years served in prison. Star tattoos on the knees indicate the prisoner bows to no one and stars on the shoulder signify captaincy in the Russian mafia.
A common prison tattoo is the tear drop below the eye. It can signify either that the wearer has murdered or is mourning the death of a loved one. According to crimelibrary.com, three dots relate to "my crazy life" among Hispanic prisoners, though they can also have religious meaning. Five dots, especially worn on the hand, indicate prison time. Four outer dots represent the prison walls while an inner dot represents the prisoner. Others, whether numbers or symbols, signify membership in a gang.