Chevrolet 1993 Astro Passenger Owner's Manual page 158

Your Driving and the Road
SWIMMING
AM402006
BROWN signs point out recreation areas or points of historic or cultural
interest.
Shape of Road Signs
The shape of the sign will tell you something, too.
An OCTI
AL (eight-sided) sign means STOP. It is always red with white
letters.
- -
A
A DIAMOND-shaped sign is a warning of something ahead-for example, the
end of a divided highway, a curve, steep hill, soft shoulder, or a narrow
bridge.
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