sentences:  When the revealing layer moves perpendicularly to layer lines, the moiré bands move along the same axis, but several times faster than the movement of the revealing layer.The GIF animation shown in Figure 4 corresponds to a slow movement of the revealing layer.The GIF file repeatedly animates an upward movement of the revealing layer (perpendicular to layer lines) across a distance equal to "p"r. The animation demonstrates that the moiré lines of the superposition image move up at a speed, much faster than the movement speed of the revealing layer.