Warning signs, Prohibitory signs and Mandatory signs
Warning Signs is a triangle which is black on yellow with a black border — warn of hazards.
Prohibitor Signs is a red circle with oblique on white — prohibiting risky behavior.
Mandatory Signs is a blue circle with white pictogram — actions required to safeguard health and avoid injury.”
Spot the shape, know the action: a triangle warns, a red circle forbids and a blue circle instructs.
Follow signs immediately.”