Crayon Physics is lots of fun; you can draw objects that immediately behave like they would in the real world.
(Crayon physics video)
If you like, you can get the download from Kloonigames and try it out yourself.
When I thought about this, I immediately remembered Sketch Furniture Ultra Rapid Prototyping. A computer system watched you draw in space with your "magic crayon" and then immediately fabricated your drawing out of actual plastic.
AI Worms That Spread
'...there were so many worms and counterworms loose in the data-net now' - John Brunner, 1975.
Technovelgy (that's tech-novel-gee!)
is devoted to the creative science inventions and ideas of sf authors. Look for
the Invention Category that interests
you, the Glossary, the Invention
Timeline, or see what's New.
Humanoid Robots Building Humanoid Robots
''Pardon me, Struthers,' he broke in suddenly... 'haven't you a section of the factory where only robot labor is employed?''
Stratospheric Solar Geoengineering From Harvard
'Pina2bo would have to operate full blast for many years to put as much SO2 into the stratosphere as its namesake had done in a few minutes.'