Zettelkasten A Tool by Niklas Luhmann en.wikipedia.org A zettelkasten consists of many individual notes with ideas and other short pieces of information that are taken down as they occur or are acquired. The notes are numbered hierarchically, so that new notes may be inserted at the appropriate place, and contain metadata to allow the note-taker to associate notes with each other. For example, notes may contain tags that describe key aspects of the note, and they may reference other notes. The numbering, metadata, format and structure of the notes is subject to variation depending on the specific method employed. zettelkasten.deHow to Make a Complete Map of Every Thought You ThinkThe Zettelkasten MethodWhat this site is notetakingthinkingwriting
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