Instructables

Ok, how the heck did they make this sweet water sensitive LED panel?

http://www.thisiscolossal.com/2012/08/water-light-graffiti-a-moisture-sensitive-surface-embedded-with-leds-creates-illuminated-art/

http://hackaday.com/2012/08/12/painting-a-wall-with-light-using-water-as-ink/#more-82288