Why is there a rotating light at the door of the barber shop?

There are revolving colored lights in front of the barber shop. It is said that during World War II, Germany sent troops to attack France, and 50,000 of them attacked a city called Pena River. The French generals stationed in this city knew that their troops were not enough to confront the Germans, so they retreated ahead of time. When the Germans entered, they were already empty. A German soldier caught a barber named Dan Keelen, a resident of the city. He told the German general that the French army had retreated to the west.

The Germans immediately pursued westward, but after more than 30 miles, there was still no sign of the French army. It turned out that they were cheated by Dan Kieran. In fact, the French army retreated eastward, and the German general was very angry and shot and killed Dan Keelen. After the war, France held a state funeral for Dan Keelen, and put his body in the Universal Memorial Hall in Paris for everyone to see. Later, the French barber salon hung a blue, white and red lamp at the door to commemorate the barber's glorious patriotic deeds. Over time, this has become the custom of barbershops.

Others:

The color bar is usually three colors, white+red+blue. Generally speaking, white = bandage, red = blood (artery) on bandage, and blue = vein. In medieval Europe, barbershops provided bloodletting therapy services. After bleeding, it needs to be bandaged. At that time, bandages were reused. Barbers are used to hanging clean bandages on the pillars at the door to dry. Gradually, this bloody bandage floating at the door became the signboard of the barber shop, which is the prototype of the red, white and blue column we see today.