it was invented in 1976 by sir Morgan Harvey
Ben Dover
An octagonal prism
A stop sign with thickness.
So that if the sign is unreadable due to snow/dirt, it can still be recognised by the shape alone.
I have two. Ones a stop sign, and the other is a lamp shade.
Stop signs are usually octagonal, so internal angles are 135°
It's an octagon. Look at a stop sign- they're octagonal.
I'm sure that it's not. It's a thick octagon.
British stop signs are octagonal to make them easily identifiable even when they are obscured by dirt or snow.
The octagonal shaped sign was colorful.
In the US, STOP signs are Octagonal (8 sided), with a bright red background and white letters saying STOP.