From root: Why no mathematical symbols?

What do the shapes mean?

The blog uses three main object types in all of the colours.

Curved boxes with labels are used primarily for data objects.

Straight boxes with labels are used for both higher-level data objects and diagram content structuring.

Circles with labels are used to define operations which act on, consume and return objects.

References and further reading

Bertin, Jacques. 1983. Semiology of Graphics: Diagrams, Networks, Maps. University of Wisconsin Press.
Hardwick, Robert J. 2026. “What do the arrows mean?” umbralcalculations, November. https://umbralcalc.github.io/posts/what_do_the_arrows_mean.html.