Before the invention of paper, thin layers of tanned sheepskin – called vellum or parchment – were used as printing material in Europe and the Near East. Ancient Egyptians used another material, papyrus, which was made from vertically sliced plant stems that were pressed and then dried. In China, characters were written on wooden or bamboo strips, which were tied together with string to form a sheet. In all of these cases, the final product took the form of a rectangle, even though the contours of dried sheepskin, for example, naturally reflected the shape of the animal. Cuneiform tablets are also rectangular when viewed from above. It seems that humans reconfigure their natural environment by making it rectangular.
Nevertheless, surprisingly few rectangular objects exist within nature with the exception of some mineral crystals, which are close to perfect cubes. Modern science is, as we are well aware, built on the order discovered in nature, so it isn't strange to find the mathematical principle of the square concealed there. Yet squares and rectangles are extremely unstable, which explains why they are so rare. Why then have people come to favor rectangular forms? One possibility is the fact that if we break a big leafy object into two pieces using our two hands, we get a straight line, while a second break results in a right angle. Another possibility comes from the nature of gravity, which turns a hanging vine or string into a straight vertical line. We could speculate endlessly on such possibilities, but the fact remains that when sheepskins were turned into writing materials, they were always cut into rectangles. This process may be understood as one of the origins of design.
Correspondingly, paper today is manufactured in the form of a roll, which is then cut into sheets that have a ratio... If we cut the sheet in half and then cut it in half a second time, this ratio stays the same – the proportional relationship between length and width remains constant. TV screens and computer monitors are rectangular but stretch sideways, reflecting the horizontal placement of our eyes.
Books are made of rectangular sheets of paper. Can we not say then that language is folded and stored in rectangular space? Basically speaking, language appears in linear form. Humans cannot utter more than a single word at a time; were that possible, communication would be even more complex than it is. When we speak, we are solo instruments. This linear structure remains the rule when our language is arranged in letters. A book is a vessel constructed by controlling this unbroken string of language, folded into a defined space.
— Kenya Hara, excerpt from White