Here’s One more optical Illusion which will confuse you.
Look at the box inside and guess if it off the same color or a grey color gradient?
Look again in the picture below in neutral background
Perceptual constancies are sources of illusions. Color constancy and brightness constancy are responsible for the fact that a familiar object will appear the same color regardless of the amount of light or color of light reflecting from it. An illusion of color or contrast difference can be created when the luminosity or color of the area surrounding an unfamiliar object is changed. The contrast of the object will appear darker against a black field that reflects less light compared to a white field even though the object itself did not change in color. Similarly, the eye will compensate for color contrast depending on the color cast of the surrounding area.