This Instructable will show you how to make a simple optical illusion. This illusion is called the Poggendorff Illusion and has been around for a while.

So what's happening in the image below? What is that red line doing there?

Go to the next step to see what's going on inside the black rectangle.

Step 1: Inside the Box

Here you can see that the blue line actually leads into the red line. Sure, the color contributes to the illusion, but it can be confusing even if the lines are all black.
I don't understand what the illusion is. Anyone care to explain?
it makes it appear as if the both lines are connected but in reality only one is to the other on the opposite side, it's a trick of the eye
Well... don't really work with me cause I got geometric vision. Since birth, I have problem to see the distance, so my deep vision rely on geometric form.
It's too bad. You should really see how fascinating the illusion is. You're definitely missing out. I wish I could help you see it.
Oh don't worry, I can still see how the illusion work, but I don't fall.
basically u see the blue line comin into the black rectangle, and u see a read and blue one coming out the other side. ur brain thinks that the blue lines are connected, when actually its the read and the blue line connected. get it?
To me the blue line on the left looks like it is between the lines on the right.
yeah I figured it out right after I posted this
lol :D
nevermind, haha now I feel stupid
this is so cool any more cool ideas then please email them to mattyts@live.co.uk
heh. I actually thought it was a trick but i guessed that the line above went between the two at the bottom :P
I fell for the trick to. Brains are so cool, I like them because there always a mystery.
Nice illusion, it is scary how easy it is to trick our brain.
Classic, but WHY does our mind do that?
nice sweet blows ur mind a little that what we see is not reality... excuse me i just finished reading the watchmen comics deep stuff
well done i liked it all<sup> lot you fooled me too</sup><br/>
im sry i sayed that worng <br/><br/>well done i liked it a lot<sup>you fooled me too</sup><br/><br/>thats what i ment to say<br/>
Very cool! First comment! nice ible. It fooled me!

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More by DoubleVision:Optical Illusion - Mysterious Black Dots Optical Illusion - Black Squares and Gray Dots Optical Illusion - Lost in Perspective 
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