The odor of raisins What would be the use, for instance, in giving the plan of the room that was really my room, in describing the little room at the end of the garret, in saying that from the window, across the indentations of the roofs, one could see the hill. I alone, in my memories of another century, can open the deep cupboard that still retains for me alone that unique odor, the odor of raisins drying on a wicker tray. The odor of raisins! It is an odor that is beyond description, one that it takes a lot of imagination to smell. But I've already said too much. If I said more, the reader, back in his own room, would not open that unique wardrobe, with its unique smell, which is the signature of intimacy. Gaston Bachelard, The Poetics of Space smellmemory
Materials and how to employ them Forming a paper clip presents a common dilemma encountered by engineers and inventors: the very properties of the material that make it possible to be shaped into a useful object also limit its use. If one were to try and make a paper clip out of wire that stayed bent too easily, it would have little spring and not hold papers very tightly. On the other hand, if one were to use wire that did not stay bent, then the clip could not even be formed. Thus, understanding the fundamental behavior of materials and how to employ them to advantage is often a principle reason that something as seemingly simple as a paper clip cannot be developed sooner than it is. Henry Petroski, The Evolution of Useful Things Ideas behind their time material