Here is a bit of background on optical illusions from wikipedia:

An optical illusion (also called a visual illusion) is characterized by visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source. There are three main types: literal optical illusions that create images that are different from the objects that make them, physiological illusions that are the effects of excessive stimulation of a specific type (brightness, colour, size, position, tilt, movement), and cognitive illusions, the result of unconscious inferences. Pathological visual illusions arise from a pathological exaggeration in physiological visual perception mechanisms causing the aforementioned types of illusions.

Optical illusions are often classified into categories including the physical and the cognitive or perceptual,^[1] and contrasted with optical hallucinations.

Once you understand why illusions happen they start to make more sense.  More than meets the eye is a saying for a reason 😉  And you have probably seen a MC Escher paintings some time before which play with this phenonena.

We hope you like the video!