It's said that necessity is the mother of invention, but the search for fun works too.
Jeroen Domburg, curator of SpriteMods.com, was making JELLO shots for a party when he got the idea to build a 3D printer that draws designs in the JELLO.
He noticed the air bubbles in his sample batch remained suspended in the JELLO, so he used a syringe to inject some green food dye in the shooters and it worked.
"I showed it to my friend, who thought this was pretty cool. 'But,' he replied, 'I don't think it's feasible to make figures by hand in all (70) of the Jello shots.'
"Never mind that," I replied, "I'll just whip up a 3D printer that can make nice figures in the jelly for you,'' Domburg wrote.
The contraption is small enough to cart around to various locations and runs off a 10 volt laptop battery.
"The final device isn't the most beautiful unit ever hacked together, but the point wasn't so much beauty as it was getting a functional printer together to make some stylish JELLO shots," Domburg wrote
He used three stepper motors from old CD-ROM drives for the X,Y and Z axes, and mounted a syringe needle on the last one.
He then used some tubing and the tray ejector from one of the cannibalized CD-ROM drives to push the dye through the needle.
Domburg then hardcoded the coordinates of a few figures into the AVRs flash memory.
Finally, he mounted the whole thing on a plank of wood, and voila!
If you want to replicate the project, or just see how it works, Domburg has released the source under the GPLv3. You can download them by clicking here.