In architecture Durer cites Vitruvius but elaborates his own classical designs and columns. In typography, Durer depicts the geometric construction of the Latin alphabet, relying on Italian precedent. However, his construction of the Gothic alphabet is based upon an entirely different modular system. The fourth book completes the progression of the first and second by moving to three-dimensional forms and the construction of polyhedra. Here Durer discusses the five Platonic solids, as well as seven Archimedean semi-regular solids, as well as several of his own invention. In all these, Durer shows the objects as nets. Finally, Durer discusses the Delian Problem and moves on to the 'construzione legittima', a method of depicting a cube in two dimensions through linear perspective. It was in Bologna that Durer was taught (possibly by Luca Pacioli or Bramante) the principles of linear perspective, and evidently became familiar with the 'costruzione legittima' in a written description of these principles found only, at this time, in the unpublished treatise of Piero della Francesca. He was also familiar with the 'abbreviated construction' as described by Alberti and the geometrical construction of shadows, a technique of Leonardo da Vinci. Although Durer made no innovations in these areas, he is notable as the first Northern European to treat matters of visual representation in a scientific way, and with understanding of Euclidean principles. In addition to these geometrical constructions, Durer discusses in this last book of Underweysung der Messung an assortment of mechanisms for drawing in perspective from models and provides woodcut illustrations of these methods that are often reproduced in discussions of perspective.

What kind of solids does Durer discuss in his fourth book?

I've been thinking about the mindwipe, now two days away. Who said that those who forget the past are doomed to repeat it? I fear that may be true for me. Add this to the reasons I write now: to remember something, perhaps even to learn -- Emil Malaquez arrived after sundown, carrying a small package wrapped in what looked like real paper. His evening dress was formal, expensive, and slightly stained, as that of all forgetful artists should be. He was a jovial man with an easy laugh, and even uglier than Tasha had suggested. I liked him immediately. "Senor Malaquez?" "Please. Call me Emil. You must be Bernardo. Tasha's told me much about you." "All of it outrageous praise?" "All of it." "Ah, she is wonderfully perceptive." He raised an eyebrow, then guffawed. "Has she said as much about me?" "She thinks you are a genius. Do come in." "Thank you."

What is the writer's name?

As food is pushed along, it undergoes digestion. Digestion is the process of breaking down food into nutrients. There are two types of digestion: mechanical digestion and chemical digestion. Mechanical digestion occurs when large chunks are turned into smaller chucks. Perhaps not surprisingly, this happens when you chew your food. Once you swallow the food, your stomach also does some of this work. Chemical digestion occurs when food is broken down into useful nutrients. This is a chemical process that begins as you start to chew your food. The saliva in your mouth starts this process. Once you swallow, the acid in your stomach further breaks down food. From the stomach, the foods moves into the small intestine. In the small intestines, another set of chemicals goes to work. Are you surprised? Your small intestine, and not your stomach, does most of the work!
What is mechanical digestion?