Biohazard Sign

All parts of the Biohazard sign can be drawn with a compass and straightedge. The basic outline of the sign is a plain trefoil, which is three circles overlapping each other equaly like in a triple venn diagram with the overlapping parts erased.

The Biohazard sign has a rich and fascinating history abaut its creation. While it seems abstract at first glance, both biologists and laymen quick and easily grasp its warning. Only fifty years ago, the symbol was absolutely unknown, but today we see the biohazard attribute in clinics, labs, and even on skateboards! This now-ubiquitous attribute was created with some thorough testing and decision making by scientists and psychologists over 40 years ago.