I definitely think this is among the best, most trippy optical illusions I have seen so far. I found it here. The facts are these: those blue and green swirls you see are actually the SAME COLOR!
If you don’t believe me, try zooming in to a small segment (like near the corner). I very sophisticatedly used my fingers to make a little square and block my eyes from the rest of the picture. It’s amazing what our eyes do! They look totally different because one has pink between each stripe and one has orange. Crazy!
Just to prove my point, I’ve filled in a section with black…now do you see it?