Don't believe everything you see.
Optical Illusions: Our mind can be fooled by incomplete visual information. As in this case in which, when we look with one eye at the concave figure of the skull, it appears to be volumetric and also gives the feeling that it follows us with its gaze when we move. This is because we need the two separate images, coming from each eye, which are recorded from different angles, for our mind to calculate the depth and volume of the figure, and since we only have one image, our mind tries to complete the information and generates the sensations of volume and movement of the skull. The way our mind works is fascinating, even to be fooled.
If you want to experience yourself, you can make this amazing skull at your home. Download the printable file here:
SKULL PDF file: https://tinyurl.com/ycc576mn