Venus is the first iPhone app that allows you to paint in the air!
The camera captures your movements in 3D, so that the stroke thickness changes with the distance to the iPhone.
Keep the phone still on a table in portrait orientation, and move your finger in front of the camera.
To stop drawing or erase, tap and hold anywhere on the screen.
To change color, just move the slider on the left of the screen ...of course without touching it!