Why I Walk An Article by Chris Arnade walkingtheworld.substack.com On my first day I literally walk across the city, to the extent it can be done…The next day I do another cross town walk, but in a different direction, filling in the blanks from the prior day’s walk. Then, over the next week(s), I walk between 10 to 20 miles per day, picking and choosing from what I have seen before, highlighting what I like, what I want to know more about, refining the path, till by the end of my trip, I have a daily route that is roughly the same. While that is certainly not the most efficient way to see a city, it is the most pleasant, insightful, and human. I don’t think you can know a place unless you walk it, because it isn’t about distance, but about content. walkinghumanitycities
Wang tiles 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. Wikipedia en.wikipedia.org Truchet TilesThe Tiling Patterns of Sebastien Truchet and the Topology of Structural Hierarchy mathalgorithms