Optical Illusions, et al

Tigeree · 2009-06-28 19:16:36

I love optical illusions! Dev's illusion worked on me. Jane's first illusion however... I know how it works but it confuses me a little... And the 2nd one, the darker circle looks higher than the other circle.

phrontister · 2009-07-28 22:47:35

This is THE most baffling optical illusion I've ever seen!

My brain absolutely refuses to see this unaided...that the shading on squares A and B is identical!!

Try these simple proofs...you'll be amazed!! :-

Copy the image (the full one, not the thumbnail) and paste it into MS Paint.
1.
- Use either the "Select" or "Free-Form Select" tool to select a portion of square B, making sure your selection stays within the square's boundaries.
- Move the selection to the white area (holding down CTRL while you move it copies the selection instead of removing that area from the canvas).
- Do the same with square A and place it next to square B.
- Compare the two shades!

2.
- Paste the image into MS Paint again.
- Choose the "Pick Color" tool, left-click on square B to select the colour, select the "Fill With Color" tool and left-click somewhere in the white area...which then changes completely to square B's colour.
- Repeat 1...and squares A & B disappear into the filled area, leaving just the two dark letters visible there!

3.
- Instead of moving the squares off the checker board just select a portion of square B and move it onto square A.
- Watch B's shade appear to change along the way!! (works the other way round too...moving A onto B).

4.
- Select a portion of square B, delete it (which should leave a blank, white patch), use the "Pick Color" tool on square A and fill B's white patch...with the 'different' shade!

Last edited by phrontister (2009-08-04 11:53:04)

soroban · 2009-07-29 03:52:29

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soroban · 2009-07-30 03:18:48

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Last edited by soroban (2009-07-30 03:22:54)

phrontister · 2009-07-30 04:18:28

1. Impossible dice - 'stacked'!
2. Impossible figure - shows what one can do with a set square that has a hidden corner.
3. Impossible triangle. Even though the mirror image of the triangle's actual construction is shown in the mirror behind it, I find it just about impossible to break the illusion - only sometimes, barely, fleetingly! My mind insists on putting the piece with "ORIGINEEL" printed on it onto the top of the vertical piece, even though it knows it's laying on the floor!
4. Another parallel lines illusion...along the 'lines' of soroban's good one. Yes - they're vertical, straight, parallel lines!

Last edited by phrontister (2009-07-30 05:59:00)

soroban · 2009-07-30 04:21:02

      * - - - - - - - - - - - - - - - *
      |       :       :       :       |
      |       :       :       :       |
      |       :       :       :       |
      |       :       :       :       |
      |       :       :       :       |
      |       :       :       :       |
      |       :       :       :       |
      * - - - - - - - - - - - - - - - *

.

      * - - - - - - - - - - - - - - - *
      |       :       :       :   *   |
      |       :       :       *       |
      |       :       :   *   :       |
      |       :       *       :       |
      |       :   *   :       :       |
      |       *       :       :       |
      |   *   :       :       :       |
      * - - - - - - - - - - - - - - - *

.

                                              *
                                          *   |
      * - - - - - - - - - - - - - - - *       |
      |       :       :       :   *   :       |
      |       :       :       *       :       |
      |       :       :   *   :       :       |
      |       :       *       :       :       |
      |       :   *   :       :       :       |
      |       * - - - - - - - - - - - - - - - *
      |   *
      *

. .

. .

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phrontister · 2009-07-30 04:39:09

Following on from soroban's good explanation of Jane's "12/13 people" illusion, here's an informative link I found today on the internet. It has some helpful illustrations:-
http://www.laurenceholbrook.com/main_00000e.htm

I also found these two illustrations.

The colour coding makes it a bit(!) clearer (I think ) to understand the illusion.

What's happening is that each person, in turn, gives an ever-increasing-height portion of their body to the next person, and after doing that with all 12 people you end up with a whole extra person.

They swap the body portion that they receive for that same portion from their own body, and give the rejected portion, combined with a further slice (about one 12th their height) from below that portion, to the next person.

The fractions are approximate, varying from person to person for best visual effect.

The process begins with the dark blue person (#1) at bottom left, who gives his hair to person #8, who gives his forehead and hair to #4, who gives the potion above the middle of his nose to #11, who gives his whole head to #6, who gives his shoulders and head to #2...and so on.

In the 13-person group you can see that all the donors have shrunk by about one 12th their original height, but the changes are subtle enough, and the figures are drawn roughly enough, for us not to notice what is really going on.

The puzzle's creator cleverly mixed up the order of the people to hide what he did.

Last edited by phrontister (2009-08-01 15:00:11)

soroban · 2009-07-30 11:12:36

.
Hello, phrontister!

A great explanation . . . Thank you for the link!
.

phrontister · 2009-07-30 11:45:05

Hi, soroban!

Thanks...all that took a bit of doing, as there's so much written about it on the net and I sifted through it as best I could. I enjoyed reading the various attempts on forums at 'simple' explanations!

I liked yours and wouldn't have bothered to post mine if I hadn't done so much work on it already.

Btw, I changed my post a bit since your post for some additional 'clarification' and to remove some duplication (I took so long to sort my thoughts out about it that our posts crossed).

Last edited by phrontister (2009-07-30 11:55:51)

Math Is Fun Forum

#26 2009-06-28 19:16:36

Re: Optical Illusions, et al

#27 2009-07-28 22:47:35

Re: Optical Illusions, et al

#28 2009-07-29 03:52:29

Re: Optical Illusions, et al

#29 2009-07-30 03:18:48

Re: Optical Illusions, et al

#30 2009-07-30 04:18:28

Re: Optical Illusions, et al

#31 2009-07-30 04:21:02

Re: Optical Illusions, et al

#32 2009-07-30 04:39:09

Re: Optical Illusions, et al

#33 2009-07-30 11:12:36

Re: Optical Illusions, et al

#34 2009-07-30 11:45:05

Re: Optical Illusions, et al

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