  In the words of the twentieth-century British mathematician G. H. Hardy, "the
human function is to 'discover or observe' mathematics" (1). For centuries,
starting from the ancient Greeks, mankind has hunted for beauty and order in
arts and in nature. This quest for mathematical beauty has led to the discovery
of recurrent mathematical structures, such as the golden ratio, Fibonacci, and
Lucas numbers, whose ubiquitous presences have been tantalizing the minds of
artists and scientists alike. The captivation for this quest comes with high
stakes. In fact, art is the definitive expression of human creativity, and its
mathematical understanding would deliver us the keys for decoding human culture
and its evolution (2). However, it was not until fairly recently that the scope
and the scale of the human quest for mathematical beauty was radically expanded
by the simultaneous confluence of three separate innovations. The mass
digitization of large art archives, the surge in computational power, and the
development of robust statistical methods to capture hidden patterns in vast
amounts of data have made it possible to reveal the---otherwise unnoticeable to
the human eye---mathematics concealed in large artistic corpora. Starting from
its inception, marked by the foundational work by Birkhoff (3), progress in the
broad field of computational aesthetics has reached a scale that would have
been unimaginable just a decade ago. The recent expansion is not limited to the
visual arts (2) but includes music (4), stories (5), language phonology (6),
humor in jokes (7), and even equations (8); for a comprehensive review, see
ref. 9.
