The first ever stop sign was created in 1914 by Detroit police sergeant Harold "Harry" Jackson, who was working as a traffic guard at a busy city intersection. One of the cross streets had a particularly low-visibility turn entering the intersection, almost always forcing Sgt. Jackson to slow down and hold back the traffic entering from that street. Looking for ways to make his job easier, he took a rectangular piece of plywood, cut off the corners to give it a distinct shape, wrote "STOP" over the center and placed facing the street. He noticed that his innovation improved the overall traffic flow through the intersection. After he shared his experience with fellow officers at a meeting, the practice started to spread across the city intersections. The next year, 1915, stop signs were adopted across Michigan. The first ones had black lettering on a white background and were 24 by 24 inches (61 cm × 61 cm), somewhat smaller than the current sign. As stop signs became more widespread, a rural-dominated committee supported by the American Association of State Highway Officials (AASHO) met in 1922 to standardize them and selected the octagonal shape that has been used in the United States ever since. The unique eight-sided shape of the sign allows drivers facing the back of the sign to identify that oncoming drivers have a stop sign and prevent confusion with other traffic signs. Another consideration of the AASHO was visibility and driver literacy, as summarized in subsequent State Highway Commission reports in the states of the U.S., was that the goal for signs "standardized throughout the Union" was that "The shape of the sign will indicate what it will mean. This has been worked up very carefully by the best qualified men in the country and men who have made a thorough study of this question. It has been found that so many people have trouble in reading the sign that the shape of the sign is very much more important than the reading matter on it." *Source - Wikipedia
A quick and easy park and grab, please bring someone tall or something to stand on if you are a bit vertically challenged.
BYOP