Feed Button
Description Presented here is a vast gallery of many different forms of Optical Illusions. Whether these optical illusions are conveyed through fractals, photographs, architecture, art, or old fashioned pen and ink, they are bound to remind you that "seeing is not believing."

Caution!!!! Some of the optical illusions on this blog may cause dizziness or possibly epileptic seizures. The latter happens when the brain can't handle the conflicting information from your two eyes. If you start feeling unwell when using this website, immediately cover one eye with your hand and then leave the page. Do not close your eyes because that can make the attack worse.
Fractal of the Day Fractal of the Day
Provided By Sprott's Fractal Gallery


Poggendorff Optical Illusion

The below flash presentation is an example of the Poggendorff illusion.

The Poggendorff Illusion is an optical illusion that involves the brain's perception of the interaction between diagonal lines and horizontal and vertical edges. It is named after Johann Poggendorff (1796-1877), a German physicist who first described it in 1860.
It can be a very strong illusion at first. Trying to line up the top and bottom lines so they meet can be tricky. Most of us though will not be fooled for long and some may not be fooled at all. I can align the two lines just about every time now. It has reached the point that I doubt if it will be a challenge for anyone. Maybe it never was a strong illusion, sometimes my memory plays tricks on me. This illusion seems to be stronger with kids.

Move one of the lines sticking out of the box until you think it matches up with the other one. Now press the button.

Do the lines match up?


Anonymous said...

One amazing thing about this illusion is that you can use another illusion to tackle it. Here's how it goes.

Look at exactly the center of the upper line for 20 sec. Now the negative (=white!) of this line is on your retina. Look at the center of the black square and move the upper line accordingly!!!

Walt said...

Absolutely Brillant! Quite unique way of tackling this illusion by using and after image illusion.

Copyright Notice
The documents distributed here have been presented on this blog in the spirit of providing an entertaining venue to educate those interested in optical illusions.

All Flckr.com photos are presented here via Flckr's "blog this" feature. This feature is enabled by each artist on Flckr. If you find material here that belongs to you and you would like to have it removed or credited please contact me and I will gladly follow your wishes.

Copyright and all rights therein are maintained by the authors or by other copyright holders. It is understood that all persons copying this information will adhere to the terms and constraints invoked by each author's copyright. These works may not be reposted without the explicit permission of the copyright holder.