3D Sketch is a small experimental drawing tool which uses the accelerometer on your android device to move the drawings you make in 3D. It's part of the android experiments initiative.
The project itself it fairly straight forward you can draw, move the phone by tilting in different directions, adjust line that you are drawing, create an animated line which pulses and re-draws itself and record an animated gif of whatever you make. Double-tapping (or hitting the trash icon in the menu) clears the app.
The way this app works is that it reads data from the accelerometer and manipulates drawings by rotating them based on the phone movement. Every new point that's entered is entered in 2D (ie, it has z value of zero) but as you move the phone it gets manipulated in 3D. Typically most graphical applications don't change the underlying points of the model but alter a matrix (a box of numbers) to manipulate the points, but here, for several reasons, it's easier and faster to actually the manipulate the points.
This application's source code is based on Zach Lieberman's inkSpace open source project under the MIT license.
You can find all the source code at: https://github.com/ofZach/inkSpace