Try as I may, I just cannot fathom this one out.
I wonder why it is called a Spine drift optical illusion then?
You'd have to ask this guy. http://www.moillusions.com/2013/02/spine-drift-illusion.html?utm_so...
W O W - freaky - it kept changing all the time,
but I got to count 12.
16 ? - ang on a tic, I'll have another go, lol!
....ok.....now from the top I can see two distinct rows of circles,
but the minute my eyes scroll down they up and disappear and
I have to start counting again....