Fair, and I don't necessarily disagree. I think this leads rather close to object oriented software being easier to reason about concretely than functional pro

Fair, and I don't necessarily disagree. I think this leads rather close to object oriented software being easier to reason about concretely than functional programming, though. And since most people are trying to get a concrete job done, that feels like a significant claim. For turtle geometry, it is also important to acknowledge the metaphor and shortcomings of a more traditionally analytic framing of drawings. Specifically, X and Y coordinates for a drawing are surprisingly hard to work with. For example, I challenge you to describe the fractal snow flake in an easier way than using directions as a metaphor. Same for the dragon curve. This can be seen akin to picking a different coordinate system, I presume?