On the Situations and Names of the Winds is the title of a fragment of a pseudo-Aristotelian treatise, most likely written by a later author of the Peripatetic school. The two-page work identifies and briefly describes the names not just of the four anemoi, but gives a wind-name to each of the twelve points of the so-called “wind-rose”, slightly less poetically the “compass rose”, which is the figure seen on classical nautical charts and maps that shows the cardinal points as well as points intermediate.
...In both agricultural and maritime settings, the names of the winds were at once practical and phenomenologically basic: to step outside and to feel them was to know how things were in the most basic sense, to “know which way the wind is blowing”, as we still vestigially say, and to find the language to speak of it.
...If I were ever permitted to teach a course on the philosophy of wind, I would begin with the questions: How did the winds lose their names? And what does it mean for us to live in a world of nameless winds? I step outside and I feel a gust. “That’s wind,” I think to myself, and I have nothing more to add beyond that. I don’t know the winds.
Wang tiles (Hao Wang, 1961) are a class of formal systems. They are modelled visually by square tiles with a color on each side. A set of such tiles is selected, and copies of the tiles are arranged side by side with matching colors, without rotating or reflecting them.
The basic question about a set of Wang tiles is whether it can tile the plane or not, i.e., whether an entire infinite plane can be filled this way. The next question is whether this can be done in a periodic pattern.
In 1966, Wang's student Robert Berger solved the problem in the negative. He proved that no algorithm for the problem can exist, by showing how to translate any Turing machine into a set of Wang tiles that tiles the plane if and only if the Turing machine does not halt. The undecidability of the halting problem then implies the undecidability of Wang's tiling problem.