In a painting called 'Catastrophe Theory' from 1983, the German painter Sigmar Polke included the math diagrams shown in the linked image below (for another image see here: https://www.sfmoma.org/artwork/2010.261/).
I'm trying to trace the source of the diagrams, i.e. the publication they were taken from.
Can anybody help me out? Even a suggestion about what they show would be helpful.
My guess is that they have to do with chaos theory or with fractals, but I really have no idea.
[Series of math diagrams, possibly of fractals]