Where good ideas come from claims innovation originates in seven realms:

1. Adjacent possibilities.Use existing components. Gutenberg used wine press for his printing press.
2. Liquid networks. 21st-century cities and the Internet make it possible for informal networks to form, enabling idea cross-pollination/inventions.
3. Slow hunch. It takes years for a hunch to evolve into an invention.
4. Serendipity. LSD, Teflon, Viagra.
5. (Unplanned/unexpected) errors. de Forest‘s development of audion diode/triode resulted from erroneous thinking.
6. Exaption. Vacuum tubes were developed for long-distance telephone/radio transmission and later used in computers.
7. Platforms. Development of TRANSIT, a precursor of GPS by Applied Physics Laboratory.