I was recently introduced to this optical illusion when my family and I attended a performance by interactive science comedian, Doktor Kaboom. To perform the illusion he mounted two flat, black-and-white spiral disks on separate handheld, reversible cordless drills. (I’ve recreated the effect here using a static image and the magic of Jasc Animation Shop.)
The effect was quite startling and a lot of fun! I won’t give it away; I’ll just explain how to make it work so you can experience it for yourself.
First, choose one of the two spinning disks and stare directly into the center of it. After a few seconds you’ll begin to experience the “tunnel effect”. Let this happen. Count to thirty (30) then immediately look at the nose on Da Vinci’s “vitruvian man”. See what happens! To reverse the effect follow the same steps looking at the other disk.
If you enjoyed the illusion, feel free to share the link using one of those handy buttons just under the post header. 🙂