Lenticular sheets consist of lens grooves on one side with coating on the back for printing images. From the lenticular lens groove side, we can see a very thin line of the image on the other side of the lenticular sheet, and this image line's location is determined by the observer's view angle. If an image is printed at each lens interval, the observer will see different images when looking from different angles.

Using this principle, we can be created to produce the following special effects

The principle of bionics tell us that our eyes see in three dimension, because our two eyes are separated horizontally, the image that each eye sees will be different. The difference or displacement determines the depth of object that we see. The brain automatically interprets this displacement as depth. This is the stereo vision principle. When our two eyes see two images from two different angles, we see the 3D effect as the real world.
For example stereo films have two images lighted by two vertical polarized lights, and a polarized glass is used to look at them. Each eye will see only one image. Some printable lenticular lens sheets can also be used to create this effect. As previously discussed, you see different image groove lines from different angles. If we place a lenticular vertical lens, where its grooves are perpendicular to the horizontal plane of our eyes, the different view angle of the two eyes will see two different image lines. When these two different image lines correspond to one stereoscopic image(consisting of two images), we will see a 3D effect.

In order to achieve a even better effect, we can use multiple images. Because our eyes are horizontal, and the lenticular groove is vertical the lenticular image must be interlaced (combined) from vertical lines of stereo images.