didn't work on me but I have trouble focusing for more than 2-3
   seconds at a time at these things. I stayed for a count of 30,
   but I had trouble sticking with the + without moving back and
   forth quickly. Also legally blind in one eye (birth) and an eye
   doc once said I have fewer "3D cells" because of it. So there's
   probably something related in all that. I dunno. But they looked
   to have the same amount at the bottom. I'm also super good at
   intuitive math for no reason... so I dunno - didn't work on me
   but I can see how going from less to more makes it appear more
   numerous than going from more to less, at least intellectually,
   even if I didn't experience it. Neat!