Why do biohazard labels consist of several circles? What does this mean?

Charles created the biohazard sign? Charles Baldwin, a retired environmental health engineer. English means biological hazard, and the word biological hazard consists of abbreviations of "biological" and "hazard". It is defined as: one or several infectious factors with direct or potential harm indirectly endanger the normal development process of people, animals and plants by directly infecting or destroying the surrounding environment. Harm to the environment and biological health caused by biological factors (such as microorganisms growing in waste from etiological and genetic experiments). The two concentric circles on the picture are like a barrel, and the three sickle-shaped symbols can be understood as ivory, rhinoceros horn and antlers. On the whole, red represents blood, and many circles represent the global crisis. . .