This panel is 2.828 times as wide as it is tall, which is a proportion of 2√2 : 1. Geometrically, this proportion results from unfolding the diagonals of two squares, which are here placed side by side. It should be noted that the foliage in the upper left and right corners of the painting actually follow the arcs of this unfolding. The right margin of the right square traces the foreleg of the dog, and the diagonal follows the axis of its nose. The left margin of the left square, similarly, passes through the shoulder of the satyr, and the falling diagonal traces his forearm, and the upper arm of the nymph. The other diagonal in this left square traces through her face and shoulder, while the comparable diagonal in the right square passes along her foot. This painting is the property of the National Gallery of Art, London, England.
This analysis was based on the image:
https://commons.wikimedia.org/wiki/File:Piero_di_Cosimo_013.jpg