Slanted Seesaw Optical Illusion

Now, I really love this one! Larry from Michigan sent me an image I couldn’t miss sharing with you. What we have here is a classic example of “Slanted Lines” illusion, just like the one we published on Monday. The usage of the effect is more advanced this time, since it additionally exploits the nature of the object presented. A seesaw (also known as a teeter-totter or teeter board) is a long, narrow board suspended in the middle. As one end goes up, the other one goes down. When we first see the example below, it looks logical that the right end went down due to heavy triangle positioned on it. The illusion shows just what you naturally expect, but the raw truth is that the seesaw is balanced perfectly horizontal, and doesn’t outweigh – nor left, nor right. You can easily prove this by squeezing your eyes, till you just see the outlines of the seesaw. Thanks for stumbling and sharing this!

Update 1 (02/22/2009): Since yesterday, I have received this enhanced animation from visitor that goes by the name Mr. Anonym. His version might help you in seeing the effect little better. You should be able to spot the moment after which the seesaw gets slanted.

Update 2 (02/22/2009): Alessandro aka SuperSandro sent another example where he modified this illusion. Now the seesaw is actually slanted, but appears perfectly balanced. Here is what Alessandro wrote – “Hi! Today I’m happy to send you this attached file. It’s the same as slanted Seesaw, but rotated for 4 degrees on the rectangle’s side. It seems to be horizontal, but of course it is not.”

35 Replies to “Slanted Seesaw Optical Illusion”

  1. This is my first ever comment!!

    Just wanted to thank you for such an Awsome collection.. keep up the Awsome work!!

    Obv, liked this illusion But I love all of them…

  2. Yea, our brains do their best and most efficient way to perceive an image but sometimes, it’s not good enough. It’s tricky sometimes to figure out why that happened.

  3. excellent!
    you dont need the downwards arrow on one end, but it helps.
    if you measure the distance, its perfectly flat. interesting

  4. I love this one! I usually don’t take much interest in the generic slanted line illusions, but this one is awesome!

  5. interesting..

    thanks to larry of michigan, mr. anonym, and alessandro for helping make it even better!

    glad to see so much participation in your illusions vurdlak!

  6. Great illusion, but I’m sorry to say the animated one is a fake. If you hide the whole animated picture except the top right triangle, you can see it moving whereas it shouldn’t.

  7. also, try holding your pointer right at the line on the seesaw. You can see the line move below the mouse on the second picture

  8. the animated gif fails, considering if you cover up the lines with your hand (ie the catalyst int he optical illusion part of things), you’ll notice the rise and fall of the triangle anyway. i’m sure it may be a proper illusion, but this gif fails in demonstrating that correctly.

  9. This actually has some practical application. I am investigating why reading putts on a golf green is unreliable, and this is the best demonstration of why. Now, If I can only figure out how to use this on the course.

  10. The last one is clearly slanted. It didn’t even cross my mind that it was supposed to look horizontal.

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