Artifcial constraints/trade-offs creating new unexpected properties. Examples: - up to 21 million Bitcoins limit - Artificial scarcity - original 140 charact

Artifcial constraints/trade-offs creating new unexpected properties. Examples: - up to 21 million Bitcoins limit - Artificial scarcity - original 140 character limit for tweets, later expanded to 280, then removed for paid users - up to 500 users per group in WeChat groupchat - ip· o· gram. ˈlipəˌgram, ˈlī- : a writing composed of words not having a certain letter (as the Odyssey of Tryphiodorus which had no alpha in the first book, no beta in the second, and so on) - wireframes vs realistic prototypes (low-fidelity vs high-fildelity) - monochrome UI for smartphones to remove distractions - feature phones vs smartphones - 1D Pac-Man - etc.