A circle segment that is as big as half a circle, or bigger,
represents elements or substances fundamental to society's
or the individual's livelihood. In chemical notation it stands
for the all-important element for earth's life forms,
In the English system of hobo signs means keep away-no use knocking, and in the same system means a good haystack for the night.
Compare with the following signs from Group 24: spring or well; the modern , water for firefighting or firefighting equipment; and .