Illusion or not?!

[Acorn]

If you isolate a section that appear to be all red, it is actually black.
Your eyes are influenced by the complementary cyan adjacent to the black to render red.
If you invert all the colours you see red/white in place of cyan/black and the illusion disappears as you cannot see anything green anywhere.
To make it work you would probably need a red/black combo.



Acorn