The 17 Device makes sound when you draw. The final drawings are a result of listening to the drawing, and have an inherent logic to them.
It uses graphite (a conductive element) as a variable resistance in a circuit connected to a speaker. The greater the resistance, the lower the pitch.
One contact is on an aluminium strip on the paper, the other is the actual graphite pencil. As you draw away from the strip, you get a lower pitch.
I made this device based on the Theremin, and on Jay Silver’s Drawdio, from the Lifelong Kindergarten group at the MIT Media Lab.