The story about the actual discovery would be too long for this website, so I present only some conclusions here.
In short, I made the discovery in May 2016 during research concerning the inaccuracy of the Rule of Thirds: I needed to know why the Rule of Thirds did not "work" (I found this out earlier). Completely unexpected I found another composition method, which I called the "Diagonal Method". After years of studying the Diagonal Method, I concluded that the Rule of Thirds does not work because it is a theory (just like the theory of the Golden Section). Some people believe in these theories, but they remain theories, or in other words: they were not discovered in existing paintings or photographs. The Diagonal Method is accidently discovered in actual works of art while not looking for confirmation of any theory, and is, by this definition, not a theory. Only when one presents this discovery to the world, it becomes a "theory".
In the following section I explain some of the phases of the discovery.