I just confirmed in the code that masterpieces are disabled for mathematical diagrams.
@_Annika_, thank you for looking into that! I have spent way too much time trying for those. I guess I can put that to bed now. I would love to see some different Mathematical Diagram options though.
I'm also updating my previous posts (rather than posting new ones) with updated images of the possible paintings, as I've discovered a lot more of them now.