Camera pointing: In bulb mode on a canon the shutter stays open as long as you hold the shutter button. If you have small light sources in a dark place then you can draw with the camera by moving it around. In this case I had a dim flash light behind a small white wooden box creating a line of light. The exposure was set very low so to get a record of the light I had to hold the camera still for a couple of seconds, otherwise there was no record of the lie of light.