Nazi concentration camp badge

Nazi concentration camp badges were colored pieces of fabric used by the Nazis to identify concentration camp prisoners during World War II.
Prisoners had to sew these badges onto their uniform jackets and pants. The badges used a color coding system to show why each prisoner had been sent to the camp. Different colors and shapes had different meanings. The prisoners were required to wear these badges of shame.
The badges helped guards assign tasks to the prisoners. If a prisoner's badge marked them as an escape suspect, the SS would not allow them to work outside the camp fence. If a prisoner had an F on their badge (meaning they were French), guards could force them to help translate instructions to new prisoners from France. If a guard looked at a prisoner and saw a green badge, the guard knew right away that the person was a convicted criminal. Guards often assigned these "green triangles" to be kapos. These were prisoners who were assigned to help the SS run the camps. Many kapos used abuse and violence to control other prisoners. 
Some historical monuments use images of these identification badges to symbolize the victims of the concentration camps.
Today, some people use a pink triangle emblem to symbolize gay rights.
Badge coding system.
Different camps used different systems of badges. In the later stages of World War II, the use of badges became less common in some camps. The following description is based on the badge coding system used in the Dachau concentration camp. This camp had one of the more detailed coding systems.
Most badges were inverted triangles. (This meant the widest part of the triangle was at the top of the shape, not the bottom.) The Nazis chose this shape because it looked like triangular road hazard signs that are common in Germany.
Single triangles.
Single triangles of different colors identified different types of prisoners.
Black triangles.
The Nazis made many different types of prisoners wear black triangles. The black triangle identified people who the Nazis called 'asocial' () or 'work-shy' (). These included alcoholics, drug addicts, homeless people, beggars, people with disabilities, prostitutes, lesbians, pacifists, and people who refused to be conscripted into the German armed forces.
Black triangles also marked Roma and Sinti people. They wore the black triangle with a Z on it (for , meaning Gypsy). Romani men were later assigned a brown triangle. However, Romani women always wore black triangles. The Nazis believed many stereotypes about Romani women. They thought these women were petty criminals (prostitutes, kidnappers, and fortune tellers). For this reason, the Nazis never stopped calling Romani women "asocial." Many of these women were forcibly sterilized.
The Nazis also used the black triangle to identify people with mental illnesses and "mentally disabled" people. Written on their badges was the word , which means "stupid." This category included people with autism. (At that time, autism was called Asperger's Syndrome, named after Austrian pediatrician Hans Asperger, who was involved with the Nazis). People with schizophrenia and epilepsy also wore black triangles. Instead of being sent to concentration camps, many people in this group were forcibly sterilized, shot, or gassed in psychiatric institutions as part of the T4 Euthanasia Program.
Other people with disabilities, like diabetes, also had to wear the black triangle. (The Nazis thought that diabetes was a 'Jewish disease.' There was no evidence for this claim. Instead, it was a result of antisemitism in medicine, science, and culture.)
Red triangles.
Red triangles identified political prisoners. These included: 
Green triangles.
Green triangles identified convicts and criminals (who often worked as "kapos").
Blue triangles.
Blue triangles identified foreign forced laborers and emigrants from Nazi-controlled countries. This category included apatrides (stateless people, who were not citizens of any country). Spanish refugees from Francoist Spain belonged to this category. Because these people did not support the dictatorship of Francisco Franco, the Spanish government cancelled their citizenship.
Purple triangles.
Purple triangles identified the Nazis' religious enemies. Over 99% of these people were Jehovah's Witnesses. Members of other small pacifist religious groups also wore purple triangles.
Pink triangles.
Pink triangles usually identified homosexual men and others who the Nazis called homosexual (like bisexual men and transgender women). The Nazis also used pink triangles to identify sexual offenders, paedophiles, and zoophiles. The Nazis forcibly sterilized many people in this group.
Uninverted red triangles.
Uninverted red triangles identified several groups of people:
Double triangles.
The Nazis used double-triangle badges to identify Jewish prisoners. These badges were made of two overlapping triangles. These two triangles formed a Star of David, a Jewish symbol.
People who wore inverted pink, green, voided black, and yellow double badges were usually convicted by criminal courts before they were sent to concentration camps.
Some double-triangle badges identified non-Jews. For example, at Mauthausen, Spanish Republicans had to wear a blue inverted triangle superimposed upon a red one.
Distinguishing marks.
In addition to color-coding, non-German prisoners were marked by the first letter of the German name for their home country or ethnic group. Red triangle with a letter, for example: 
Polish emigrant laborers originally wore a purple diamond with a yellow backing. A letter P (for "Polen") was cut out of the purple cloth to show the yellow backing beneath.
Furthermore, repeat offenders (, meaning recidivists) had to wear bars over their stars or triangles. Different colors represented different crimes: 
Later in the war (late 1944), to save cloth, Jewish prisoners wore a yellow bar over a regular point-down triangle to indicate their status. For instance, regular Jews would wear a yellow bar over a red triangle, while Jewish criminals would wear a yellow bar over a green triangle.
Postwar use.
Triangles appear on many postwar memorials to the Nazis' victims. These shapes represent the identification patches used in the camps. Sometimes, plain or colored triangles represent all categories of inmates. Often, inverted red triangles represent all victims of the concentration camps, including also the non-Jewish victims like Slavs, Poles, communists, homosexuals, Roma and Sinti, people with disabilities, Soviet POWs, and Jehovah's Witnesses. 
Some Holocaust memorials use more specific triangles. An inverted pink triangle symbolizes gay victims. A yellow and/or non-inverted triangle generally stands for Jewish victims. Some monuments also include badges with nationality letters.
2020 Trump campaign.
In June 2020, Donald Trump was running for re-election. His campaign posted an advertisement on Facebook which said that "Dangerous MOBS of far-left groups are running through our streets and causing absolute mayhem." The ads identified these groups as "ANTIFA" and used an image of a downward-pointing red triangle. These ads appeared on the Facebook pages of Donald Trump, the Trump campaign, and Vice President Mike Pence. Many observers compared the graphic to the symbol used by the Nazis for identifying political prisoners such as communists, social democrats and socialists. Many noted that there were 88 ads. Neo-Nazis use the number 88 as an abbreviation for the Nazi salute "Heil Hitler". (The letter H is the eighth in the alphabet, so 88 stands for "HH.")
Facebook removed the campaign ads that used the red triangle symbol, saying that its use in this context violated their policy against "organized hate". The Trump campaign's communications director wrote that "The red triangle is a common Antifa symbol used in an ad about Antifa." However, the historian Mark Bray, who wrote "", disagreed. He said that the symbol Antifa in the United States does not use this symbol.
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