I'll be among the first to admit, this little Pycon-length talk on @decorators (in a math-learning context) has its weaknesses: https://youtu.be/bQOrmiufSSc?list=PLeBIlkJm4xgnJd1B8AOLIIuclk0ayXlR8 Mainly, I'm "showing my age" (somewhat literally) in that my non-data descriptor, age, doesn't really get into the action the way I claim, given how descriptors without a __set__ rank lower on the MRO totem pole. However, I do wonders with "color". :-D The playlist immediately segues to a San Francisco User Group presentation on the same topic, where Simeon does a better job explaining the rules (MRO). Given my geometric focus, the rest of the videos veer into spatial geometry, wherein I continue to use Python, sometimes Visual Python. Kirby