A 4-variable Karnaugh map can be thought of, topologically, as being a torus.

[T]he death of the said deceased Daniel Docherty, while in the defender's employment as an engineman, […] is alleged to have been owing to the engine house, which contained the engine of which the deceased had charge, being of a dangerous and improper construction, and the fly-wheel not having been boxed in or covered: […]

And, beside this kind of work in retiary and hanging textures

Benedict used a tungstomolybdic acid solution for precipitating the proteins, but the Folin-Wu filtrate can be used.