If there is an object known to everyone, even to savages, and one that can be used to indicate direction, that object is the arrow. The arrow leaves a taut bow and always flies in the direction of its point.
Whoever chose the arrow as a signal to indicate direction must evidently have thought of this. And of course, for this purpose, it doesn’t matter if the arrow is made of ebony, teak or a willow wand, if the arrowhead is made of forged iron or tiger’s bone, or whether the flight that keeps it on a straight course is made of feathers endowed with magic powers to guide it to its mark. What matters is the shape.
Taken from “Design as Art” by Bruno Munari.