# Thread: Funny trick

1. dec
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Not totally sure but I know Im not paying to find out. I see sigma isnt going to pay either...lol

2. I have a cutout of that trick that I have been looking at once in a while for years trying to figure it out. I know it's a trick so I'll be damned if I am going to pay to know how it is done.

3. Professional Member
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Well, the original triangle area should be 32.5 sq units(1/2 X 13 X 5), and all the shape areas add up to 32 sq units before the "magic" and 33 sq units(with the missing piece included) afterwards, so there's already a difference of one sq unit. I wonder if it isn't in the borders...

4. Guy
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That's an old one. If you look at the "triangle" before the pieces have been rearranged to show the missing square, you will notice that the hypotenuse (the sloped side) is not straight, but has a slight inward "bump" in it. Just examine where it crosses the grid lines at 5 squares to the right and 2 squares up from the lower left corner of the triangle: the line is slightly below the intersection instead of going straight throught it.

Now watch that point during the animation. While the L shaped piece is being moved downwards, you will see the line rise from slightly below the intersection to slightly above, creating an outward bump instead. Well, the difference in area between the inward bump and the outward one, when stretched to the two ends of the hypotenuse, is exactly one square...

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Could they have made that woman any uglier?

6. Could they find background music that was more annoying?

7. ## Could she speak

freaking english?

8. dec
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we could take up a collection to find out the answer......oh wait lets just get some beer. Then we wont care why its differant.

9. The hypotenuse is not straight, with a run of 13, and a total rise of 5, the center (6-1/2) should fall exactly at 2-1/2. It doesn't.

And if you watch each piece slide in and out of the boarder, you'll notice that a few of the pieces start out touching the inner edge of the boarder and end up touching the outer edge.

The bent hyponenuse only hides the fact that the two triangles are different shapes. The secret is that the triangles move from the inside edge of the border to the outside edge.

In my opinion.

10. I got a graph paper and drew the big triangle. Then I cut out all other pieces making this triangle.
First thing I noticed was that red and blue triangles are not connected in one point but they slightly overlap.
I think that this fact is what makes a difference after all pieces are rearranged.
In order to fit all pieces into big triangle after rearrangement, they have to hang bellow horizontal side of the big triangle about 1/8 of the square.
Horizontal side has 13, so 12x 8 = 96/8. Square has 64/8 so in reality the void is actually bigger then one square.
Like some of you noticed this illusion is created by thick border line and bowed hypotenuse.

And I would never pay either, to find out the answer

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There was no need wasting your time. Guy is correct. If you look at the point in the second picture, it buldges out a tiny bit. This is because the hypotenuse is not straight. That creates enough area to form the square.

[Edited by James 3528 on 05-26-2005 at 10:06 AM]

12. We all owe Guy a \$1.

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