Idiosyncratic paragraphs Text-only paragraphs differ from one another only in their words. All the words are typographically the same – typeface, spacings, line-lengths piled up into long deep columns. Systematic regularity of text paragraphs is universally inconvenient for readers, who are unable to find and read once against a specific string of words in previously-read paragraphs. All readers have encountered this problem in essays, articles, novels, news reports. Idiosyncratic paragraphs assist memory and retrieval by readers, by uniquely activating the relevant neural substrates for retaining visual memories. Nearly every paragraph in this book is deliberately unique. Edward Tufte, Seeing With Fresh Eyes variation
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