Definition: Rectanglophilia is a characteristic of visual arts in the Anglo-American historical era to trend toward a preference for rectangles. Likely, this is a result of philosophical doctrines of the era which contend the world is best understood as a series discrete, binary, abstractions. See: Scientific Revolution, Enlightenment, Liberalism, Industrial Revolution, Modernism, Neo-Liberalism, Post-Modernism.
A few examples…
Some Comfort Gained From the Acceptance of the Inherent Lies in Everything , 1996 - Damien Hirst
1024 COLOURS, 1973 - Gerhard Richter
Mark Rothko, Circa 1950s
Tableau I, 1921 - Piet Mondrian
Girl With a Mandolin, 1910 - Pablo Picasso
Vincent van Gogh, Self-Portrait, oil on board, 1887
A Sunday Afternoon on the Island of La Grande Jatte, 1884 - Georges Seurat
And a very small sample of the same again in architecture…