What is the origin of Guanyin sign?

Regardless of Buddhism, Taoism and other folk beliefs, they all respect and rely on the equality and compassion of Guanyin Bodhisattva. According to Buddhist classics such as The Complete Book of Avalokitesvara and The Original Wish of the Earth-hidden Bodhisattva, Avalokitesvara has a deep relationship with all living beings in this world. After Buddhism flowed into the Central Plains and merged with the local religious culture, in order to cater to the psychology of some believers, the Guanyin sign gradually came into being. Things like arhats often indicate the fortune of fortune tellers in the future and their current situation. Or four sentences, or quatrains, etc. But Buddhism does not advocate these practices in essence. To some extent, the hat of superstition is wrongly attached to Buddhism, which is not unrelated to these things. Buddhism guides the public to have a positive view, starting from the cause, "all evil should be avoided and all good should be done", in order to get what they want, everything goes smoothly and benefit others and themselves.