I have Three cig burns out marks into a triangle shape, between the pointer and thumb.
This is also popular in German prisons among current and former convicts as a symbol of their time done behind bars. Generally it implies the person does not know, see or hear anything and has therefore no information for the police. This tattoo also usually appears on the skin between the thumb and forefinger. Also for some groups it means 'I hate cops.'
In France, the dots stand for 'Mort Aux Vaches', literally 'Death to cows', in slang 'Death to cops'. It can also be interpreted as '**** the World'. In Greece, the three dots in a triangle signify affiliation with anarchist beliefs/ideals (The three dots can be seen as points of the letter "A", the symbol for many anarchists around the world).
The three dots in a triangle are also used as a protective symbol for hobos, sailors, and convicts, known as "hobo dots." Among sailors it's a traditional tattoo to get on their first voyage.
The three dots in a triangle are also used widely in the southeast region of Turkey as a symbol of being one of the tribesmen. The three dot symbol is known as "Gormem, Duymam, Soylemem" meaning that "I hear nothing, I see nothing and I tell nothing". Bearing this mark is an oath to the person's own society, and requires great responsibility such as being willing to sacrifice himself in favor of the society.