Visual 3D Optical Illusion

Optical illusions and brain games in the ability of the eyes to capture images in 3 dimensions.
I present optical illusions called "Stereograms", is an optical illusion based on the ability of the eyes to capture images from different points of view.
These different perspectives are captured in such a way by the brain, which seems to be a three-dimensional image.
Instructions:
TECHNIQUE ONE: look at the image without focusing the view anywhere. After a while, you begin to "feel" that something happens. The image will begin to change, when you notice that this happens, stay relaxed and continue doing the same.
Your eyes will do the rest of the work. First you will see only part of the image. Continue the same and you will observe how the rest emerges in an amazing way.
TECHNIQUE DOS: Put a few centimeters of the image. Let your eyes get used to seeing the image from close up.
Then without allowing the focus to move slowly until you reach a length of your arms stretched from your eyes to the image, relax and you will get to see it, if you do not repeat it again.
TECHNIQUE THREE: This is the so-called "vision through" method.
It is achieved by focusing the look beyond the two-dimensional image so that it is crossed, as if you wanted to see something through the image.
Imagine that behind the image there is an object in the distance and focus your eyes to try to see it if you hold that way for a few seconds you will get to see the image.