Lenticular printing is a technology in which lenticular lenses (a technology also used for 3D displays) are used to produce printed images with an illusion of depth, or the ability to change or move as they are viewed from different angles. Examples include flip and animation effects such as winking eyes, and modern advertising graphics whose messages change depending on the viewing angle. Colloquial terms for lenticular prints include "flickers", "winkies", "wiggle pictures" and "tilt cards". The trademarks Vari-Vue and Magic Motion are often used for lenticular pictures, without regard to the actual manufacturer. Process Lenticular printing is a multi-step process which consists of creating a lenticular image from at least two images, and placing it behind a lenticular lens. It can be used to create frames of animation, for a motion effect; offsetting the various layers at different increments, for a 3D effect; or simply to show sets of alternative images that appear to transform into each other. Once the images are collected, they are arranged in individual frame files, then digitally combined into a single file in a process called interlacing. The interlaced image may be printed directly on the back (smooth side) of the lens, or on a substrate (ideally a synthetic paper) which is laminated to the lens. When printing on the backside of the lens, the critical registration of the fine "slices" of interlaced images must be absolutely correct during the lithographic or screen printing process to avoid "ghosting" and poor image definition. The combined lenticular print shows two or more images by changing the angle from which the print is viewed. If a sequence of images is used, it can even show a short animation. Though normally produced in sheet form by interlacing simple images or colors throughout the artwork, lenticular images can also be created in roll form with 3D effects or multi-color changes. Alternatively, several images of the same object, taken from slightly different angles, can be used to create a lenticular print with a stereoscopic 3D effect. 3D effects can be achieved only in a lateral (side-by-side) orientation, as each of the viewer's eyes must see them from a slightly different angle to achieve the stereoscopic effect. Other effects, like morphs, motion, and zooms work better (with less ghosting or latent effects) in top-to-bottom orientation, but can be achieved in both orientations. There are many commercial processes in the manufacture of