Have you ever wondered how to create a cool photo this?
T3h_Muffinator has posted a nice step-by-step (basic) tutorial on painting with light at Instructables;
“Press the capture button, run to wherever your camera is focused on, and turn on your light source. Draw the picture you want, trying not to shine the light source directly at the camera. This will produce a “twinkle” where you shined it from (see picture). If you want to stop a line segment and start a new one, you can cover the light source with your hand and move it over to where the new line segment will start. If you have a flashlight, just turn it off, move it over, and turn it back on! < -- Much easier!"