WHAT!?!!

I have found the most mind-boggling optical illusion I've ever seen. Usually it's the kind of thing when you look at a picture and then think that one line's longer than the other and then get told that they're the same size and you can (if you look closely enough) see that yes - line number one is, in fact, the same length as line number two. And the same rule applies to squares that look like circles, triangles that are not drawn (only implied) and so on and so forth. But then I came across this little beauty:

The question posed was this: Which is darker? Square A or square B? Now this is not a difficult question. With optical illusions you always answer the least obvious? If square A was red and square B was blue and the question reads "which is the blue square?" you would point to square A. After some careful study of the two you would come to realise that yes indeedio square A was actually the blue square and square B was in fact a shade of turquoise that was so striking that, when placed next to square A, made it look red by comparison. So when the question asks "which is darker" and square A is quite clearly the darker square then the answer can only be either square B is the darker square or both squares are exactly the same shade of grey. But in this case there is no way that square B is the same shade (or darker) than square A. No matter how hard you study it, square A is quite visibly the darker square. So what's the catch? That square A is actually red? That the darker square is actually square C which is situated under the giant green cylinder? That square A is in fact darker and optical illusions are just getting lazier.

No!

I scroll down and find (surprise surprise), both these squares are the same shade. This was quite clearly not true. I have looked at this picture for quite some time and I can assure you that that alphabetically first square is in fact a darn sight darker than the alphabetically second. Some mistake has been made here surely?

So I did a little digging. I copied the picture onto paint, sampled the colour of one and then painted a line from square B down to square A. Here is the result:

Right! So it would seem that somehow the colours match. But I still wasn't comfortable. If you look closely, it seems that the bridge from A to B seems to lighten in shade as it makes its way to the lighter grey. Maybe there's some kind of programme that won't allow it to maintain the same level of greyness. Maybe it took the wizarding software of Microsoft Paint into account when it was being designed. Probably not. But the colours still looked different to me. So I cut them out of the picture altogether:

Ah now that's clever. It was the same colour the whole time but with the fine art of Visual Trickery I was made to think that square B was distinctly lighter than square A. However, now that I have disected it and learnt how it works and discovered that they are in fact the same colour, I will now be able to see as much in the original piece right?

Wha...? But it's... STOP MESSING WITH MY HEAD!!!!