Different shapes of signs represent different meanings:

Equilateral triangle: used for warning signs

Circular: used for prohibition and indication signs

Inverted equilateral triangle: used for "slow down and give way" prohibition sign

Octagonal shape: used for "parking and yielding" prohibition signs

Fork shaped: used as a warning sign for "fork shaped symbols at railway level crossings"

Square: Used for directional signs, some warning, prohibition, and indication signs, tourist area signs, auxiliary signs, notice signs, etc

Except for a few signs, the color of the border of the sign should be consistent with the color of the graphic or character of the sign, and the color of the border of the sign should be consistent with the background color of the sign, except for indicating signs.