When the topic of literate programming comes up, there’s a tendency to bemoan a lost art. A lot of people complain that, while Knuth’s WEB system allowed the user to write their code in whatever order made sense for the narrative, modern so-called “literate programming” tools more or less just extract all the code blocks from a markdown file, constraining the presentation format to whatever order the computer demands. What this analysis misses, I think, is that this is much less of a constraint with modern programming languages.

A friend wanted to 3D-print a shape to demonstrate using calculus to find the volume of solids of known cross-section. The shape he wanted was a graph of $sin(x)$ vs $x^2$, where each vertical slice of the intersection was a square. Here's the graph, with $y_1 = sin(x)$ and $y_2 = x^2$. The blue lines show the edge of each square. He couldn't figure out how to do this in a CAD program (I'm not even sure if it's possible), so he asked me if I could write some code to render it.