The praxinoscope is an animation device giving the illusion of motion, it was patented in 1877 by Reynaud and was popular from that time. The device is similar in some ways to the zoetrope in that it consists of a cylinder that can be rapidly spun and which holds a strip of images showing phases of movement. The images are viewed in a set of mirrors arranged in a polygon. The mirrors are set halfway between the edge of the cylinder and its centre, the image reflected by the mirrors will therefore lie at the axis of the cylinder and remain stationary. When the cylinder is spun the strip is in continuous motion, the mirrors reflect successive images towards the viewer, although, when the edge between two mirrors is facing the viewer half of one image and half of the next image will be seen.