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.
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.
A System To Defeat AI Face Recognition
'...points and patches of light... sliding all over their faces in a programmed manner that had been designed to foil facial recognition systems.'
Smart TVs Are Listening!
'You had to live -- did live, from habit that became instinct -- in the assumption that every sound you made was overheard...'