Just like Colin (the person who submit this flick), I have seen this illusion many years ago. After a while, it kept following me throughout the internet, and I was bumping on it in regular time intervals. Somehow, I never felt it was complex enough to post on this site. The problem was that it was a static image, with both vertical 12, 13, 14 and horizontal A, B, C printed at same time. Luckily, Colin found this very same illusion, but in animated mode. It works much better, I think.
Unfortunately, if you are following us through “Optical Illusion of The Day” widget (those of you who missed it, be sure to get it here) you won’t see an animation – instead a static pic. This is a modification we’ve recently added to keep the apps stable.
Anyway, as simple and beautiful it is, this illusion clearly shows how CONTEXT plays a crucial role in our understanding of what we see. Can you force yourself to see the sequence as 12, B, 14 or A, 13, C instead? This is what Colin added to his submission:
I remember seeing this illusion many years ago at school. When the animated GIF plays, the B/13 in the centre remains exactly the same. It’s your brain who changes the context it’s seeing it in, and reads it differently – Colin