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.

Radiation Sign

The international radiation sign (trefoil) first appeared in 1946, at the University of California, Berkeley Radiation Laboratory. At the time, it was rendered as magenta, and was set on a blue background. The modern adaptation is black against a yellow background, and it is drawn with a central circle of radiuss R, an centralized radius of 1.5R and an external radius of 5R for the blades, which are afar from each other by 60В°.

Trefoil

Trefoil (from Latin trifolium, "three-leaved plant", French trefle, German Dreiblatt and Dreiblattbogen) is a clear form composed of the outline of three overlapping rings acclimated in architectonics and Christian symbolism. The term is aswell activated other symbols of three-fold shape.

Trefoil is a term in Gothic architectonics given to the ornament foliation or cusping introduced in thehead of window-lights, tracery, panellings, etc., in which the center takes the form of a three-lobed leaf (formed from three partially-overlapping circles). One of the ancient examples is in the plate architecture at Winchester (1222 - 1235). The fourfold adaptation of an architectural trefoil is a quatrefoil.

A trefoil accumulated with an equilaternal triangle was aswell a moderately accepted symbol of the Christian Trinity during the late Middle Ages in some locations of Europe.