Because Fan Bingbing's signature is one of the biggest differences with others. He has no left-right structure, but a top-down structure. The bottom edge is very long, and the word ice and ice together looks like one meter. So Fan Bingbing's group looks very indecent. Even so, Fan Bingbing has not changed his style. If Louis Koo is the most unique signature among all the stars, then Louis Koo's signature is casual, so watching Louis Koo sign someone else's name is like joking.
I can only see that his hand keeps drawing circles, because Louis Koo's signature belongs to writing an ancient word first, and then extending downward at the end of the ancient word. Its structure is roughly the same as that explained by Fan Bingbing, and it will draw circles repeatedly, not just two circles, but an infinite loop, depending on Louis Koo's patience and time.
At the award ceremony of the movie party, the stars always sign their names after walking down the red carpet, while Louis Koo draws the signature card from the first volume to the bottom, so Louis Koo is a funny signature and a wonderful signature. Many fans want to get Louis Koo's autograph, but to be honest, Louis Koo's name is easy to imitate. I have learned his signature method after reading it once.