Z is for . . .

The final Mad-Cool-Math Nugget is . . . the Zollner illusion.

Image courtesy: Wikipedia

Besides making you go cross-eyed, the purpose of this optical illusion is to make your brain doubt that the diagonal lines in this image are parallel. The shorter lines set on angles mess with your perception. This illusion is named for the person who designed it: German astrophysicist Johann Karl Friedrich Zöllner. (Wikipedia)

Want to see more? Go to this Wikipedia page. I grabbed a few of my favorites to share here.

In this Simultaneous Contrast illusion, the background changes from dark grey on the left to a lighter grey on the right. Believe it or not, the bar in the middle is one shade of grey. Yes, really.

Image courtesy: Wikipedia

In this next one, focus on the black dot while you move your face closer to and then away from the screen. Don't go too fast. We don't want any broken noses. The outer rings should appear to rotate. Trippy.

Image courtesy: Wikipedia

And finally, the dancer. Is she moving clockwise or counterclockwise? The first time I saw this she seemed to switch direction after a second and danced clockwise from then on. I keep trying to see her dance counterclockwise, but my mind isn't cooperating. Typical. (I was also one of those people who saw "The Dress" as cream and gold.)





By Nobuyuki Kayahara (Procreo Flash Design Laboratory) [CC BY-SA 3.0], via Wikimedia Commons

And that's all folks! Sing it with me: Now I've blogged my ABCs, next time won't you blog with me!

 It's been a blast. Thank you to all who've stopped by, commented, followed, and maybe even made off with a free download of one of my stories. Special thanks to those bloggers who kept coming back for more despite the math theme, including

Chrys Fey at Write With Fey

Nick Wilford at Scattergun Scribblings

Cold As Heaven

Rena Rocford at Doctor Faerie Godmother

Lynda Grace An Hour Away

Sarah Foster at The Faux Fountain Pen

Keith's Ramblings

Mark Coopman at Viginette's from VA (and D.C. too!)

Alex J. Cavanaugh

If I forgot anyone, my sincere apologies. See Read you next week at the IWSG!

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Finally, if you missed any of the free downloads from my new collection Ursa Major And Other Stories, the price is reduced today through the month of May.