A late change in requirements is a competitive advantage A Quote by Mary Poppendieck The State of Agile Software in 2018YagniComplete and consistent requirementsWelcome changing requirements agilesoftwaredesign
207. Good Materials Problem There is a fundamental conflict in the nature of materials for building in industrial society. Solution Use only biodegradable, low-energy-consuming materials, which are easy to cut and modify on site. For bulk materials we suggest ultra-lightweight 40–60 lbs. concrete and earth-based materials like tamped earth, brick, and tile. For secondary materials, use wood planks, gypsum, plywood, cloth, chickenwire, paper, cardboard, particle board, corrugated iron, lime plasters, bamboo, rope, and tile. Christopher Alexander, Murray Silverstein & Sara Ishikawa, A Pattern Language Zeniba's house material