A lens projects an image of the scene in front of it directly onto the disk.[3] Each hole in the spiral takes a "slice" through the image which is picked up as a pattern of light and dark by a sensor. If the sensor is made to control a light behind a second Nipkow disk rotating synchronously at the same speed and in the same direction, the image will be reproduced line-by-line. The size of the reproduced image is again determined by the size of the disc; a larger disc produces a larger image.