an optical illusion is always characterized by visually perceived images that, at least in common sense terms, are deceptive or misleading. Therefore, the information gathered by the eye is processed by the brain to give, on the face of it, a percept that does not tally with a physical measurement of the stimulus source....which, thanks to wiki, is another way of saying that this image is inverted to maximuse it's impact!
well well lovely shot let me say at first. clever use of the inversion nice tones as well.. well handled post processing too deft as usual.. well seen opportunity
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