The golden ratio.
The proportions of the golden ratio pop-up in all sorts of places in Nature and man-made things since early times and are a handy shortcut to make something we seem to find pleasingly proportioned. In photography, art, Nature, violins, or the Parthenon, we just keep being drawn to it. It has a pleasing equation too where the ratio of the long over the short dimension is the same as both added together over the long dimension. Why not browse some golden ration examples. Even Trump.