In nature, the Golden Ratio can be found in the shape of our galaxy, the crest of a wave, the branches of a tree, pine cones, flowers, shells and various other elements. In fact the prevalence of the ratio in our world is thought to be the reason for the inherent sense of beauty created when it is used in visual art.
How to Lay Out a Phi Based Canvas
To properly lay out a phi designed canvas draw a diagonal from one corner to the opposite, from that diagonal draw a line at 90 degrees to a third corner. Then draw horizontal and vertical lines through the intersection point. If the grid is not to be subsequently divided the intersection point should be the focal point of the composition (often this is the horizon line). Countless subdivisions can be created to ensure balance throughout the work.
Examples of phi based art can be found in the works of Da Vinci, Raphael, Monet, Dali and countless others. Da Vinci spent years perfecting his "phi framework" and used it throughout his art as well as his design work.
Perhaps Pacioli was referring to the sense of perfection he felt when viewing art designed around phi.