4 October 2009 Same Colour Illusion

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Expand view Topic review: 4 October 2009 Same Colour Illusion

Re: 4 October 2009 Same Colour Illusion

by bystander » Fri Oct 09, 2009 3:44 am

NoelC wrote:Art is illusion, illusion is Art.
We have it on good authority, Art is just an illusion, feel free to ignore him. :mrgreen:

Re: 4 October 2009 Same Colour Illusion

by geckzilla » Fri Oct 09, 2009 3:00 am

It was on the same test making sure we knew the chemical symbols. The symbol was listed and then we had to write in the name of the element. The instructions did state and she made sure we knew that we would be graded on our spelling. I didn't mind but was pretty burned by that 1 point shy of perfection.

Man, all I have are bad memories from that class. I remember she was teaching us about hydrogen and mentioned tritium being radioactive so of course I put two and two together in my mind and blurted out the question, "Is that what they use to make hydrogen bombs?" and everyone looked at me like I had just asked the most inappropriate question ever, like I wanted to build one and blow everyone up or something. I really enjoy science but my peers and the teacher made my chemistry class unbearable.

Re: 4 October 2009 Same Colour Illusion

by Chris Peterson » Fri Oct 09, 2009 2:19 am

geckzilla wrote:I spelled sulfur as "sulphur" on my chemical spelling test in high school chemistry class and the teacher counted it wrong. It marred my perfect score. :cry:
"Sulfur" is certainly the preferred spelling in the U.S., but "sulphur" is an acceptable spelling. That was a bad teacher you had- all the more since penalizing for spelling on a chemistry exam isn't very reasonable.

Re: 4 October 2009 Same Colour Illusion

by geckzilla » Fri Oct 09, 2009 1:20 am

I spelled sulfur as "sulphur" on my chemical spelling test in high school chemistry class and the teacher counted it wrong. It marred my perfect score. :cry:

Re: 4 October 2009 Same Colour Illusion

by neufer » Wed Oct 07, 2009 2:28 pm

jerbil wrote:I truly enjoyed the spelling exposition on the use of the "u" in vario(u)s words in the English language. As a Brit I tend to object to some substitions of "f" instead of "ph", for example in the word "sulfur." On the other hand, with the huge contribution to American culture of the Spanish influence, in which the "f" is obligatory, it is understandable.

Quite apart from these etymological discussions, I am amazed that pregnancy has come into the discussion, and I am a male.
Then it's probably OK phor you to phollow Rob's procedure:
Rob_K wrote:Head sideways, cross eyes, move square A over square B, and run them around a little so there's a bit of overlap.

Re: 4 October 2009 Same Colour Illusion

by haemodomru » Wed Oct 07, 2009 1:36 pm

i played this puzzle to compare A and B :D
http://www.puzzcore.com/game/091007SJ5T

Re: 4 October 2009 Same Colour Illusion

by Redbone » Wed Oct 07, 2009 12:21 pm

Re: 4 October 2009 Same Colour Illusion

by jerbil » Wed Oct 07, 2009 6:02 am

I truly enjoyed the spelling exposition on the use of the "u" in vario(u)s words in the English language. As a Brit I tend to object to some substitions of "f" instead of "ph", for example in the word "sulfur." On the other hand, with the huge contribution to American culture of the Spanish influence, in which the "f" is obligatory, it is understandable.

Quite apart from these etymological discussions, I am amazed that pregnancy has come into the discussion, and I am a male. What a "fertile" thread this has become!

Re: 4 October 2009 Same Colour Illusion

by NoelC » Tue Oct 06, 2009 3:37 pm

Art is illusion, illusion is Art.

:)

-Noel

Re: 4 October 2009 Same Colour Illusion

by Carl Horn » Tue Oct 06, 2009 9:36 am

Seems I answered the post at the bottom of page 1 without realising there were already several postings on page 2. :oops:

Re: 4 October 2009 Same Colour Illusion

by Carl Horn » Tue Oct 06, 2009 9:33 am

G'day, David, It's my understanding that something had to cast a shadow so that square B would actually be darker, although our mind's eye would see it as remaining 'white', so why not a green cylinder? Would you have preferred a blue cube? :wink: Cheers, Carl (PS I'm glad I started this thread - some interesting, educational, and entertaining comments).

Re: 4 October 2009 Same Colour Illusion

by DavidLeodis » Mon Oct 05, 2009 4:55 pm

neufer wrote:
Chris Peterson wrote:
DavidLeodis wrote:Thanks bystander. So the illusion will still work if the cylinder was removed but the faint shadow was retained.
But it won't work as well, and for some people it won't work at all. The brain needs to interpret the darker area as a shadow.
Without something visible to cast it, the dark area may not be interpreted as shadow, and the illusion can be spoiled.
http://www.rense.com/general4/hg.htm wrote:
"Now wait a minute! I see something on top of the cylinder. No, it's nothing but a shadow. Now the troops are on the edge of the Wilmuth farm. Seven thousand armed men closing in on an old metal tube. Wait, that wasn't a shadow! It's something moving . . . solid metal . . . kind of shieldlike affair rising up out of the cylinder . . . It's going higher and higher. Why, it's standing on legs . . . actually rearing up on a sort of metal framework. Now it's reaching above the trees and the searchlights are on it. Hold on!"
Clever neufer. I'm beginning to understand the illusion now! The cylinder is actually a little green man from Mars. Quick, we need Tom Cruise. :) :mrgreen:

Re: 4 October 2009 Same Colour Illusion

by neufer » Mon Oct 05, 2009 2:22 pm

Chris Peterson wrote:
DavidLeodis wrote:Thanks bystander. So the illusion will still work if the cylinder was removed but the faint shadow was retained.
But it won't work as well, and for some people it won't work at all. The brain needs to interpret the darker area as a shadow.
Without something visible to cast it, the dark area may not be interpreted as shadow, and the illusion can be spoiled.
http://www.rense.com/general4/hg.htm wrote:
"Now wait a minute! I see something on top of the cylinder. No, it's nothing but a shadow. Now the troops are on the edge of the Wilmuth farm. Seven thousand armed men closing in on an old metal tube. Wait, that wasn't a shadow! It's something moving . . . solid metal . . . kind of shieldlike affair rising up out of the cylinder . . . It's going higher and higher. Why, it's standing on legs . . . actually rearing up on a sort of metal framework. Now it's reaching above the trees and the searchlights are on it. Hold on!"

Re: 4 October 2009 Same Colour Illusion

by Chris Peterson » Mon Oct 05, 2009 1:57 pm

DavidLeodis wrote:Thanks bystander. So the illusion will still work if the cylinder was removed but the faint shadow was retained.
But it won't work as well, and for some people it won't work at all. The brain needs to interpret the darker area as a shadow. Without something visible to cast it, the dark area may not be interpreted as shadow, and the illusion can be spoiled.

Give 'em the old razzle dazzle.

by neufer » Mon Oct 05, 2009 1:56 pm

bystander wrote:
DavidLeodis wrote:Is there a particular reason why the green cylinder is there (assuming it is green and not an illusion! :) ) as the illusion works without it. :?:
To supply the shadow, without which there is no illusion. As to why it's green :?:
I suppose any non-grey scale color would work.
    • Memorable quotes for _Chicago_ (2002)
    Billy Flynn (Richard Gere): Give 'em the old razzle dazzle. Razzle razzle 'em.
    Give 'em an act with lots of flash in it and the reaction will be passionate.
http://en.wikipedia.org/wiki/Dazzle_camouflage wrote:
<<Dazzle camouflage, also known as Razzle Dazzle or Dazzle painting, was a camouflage paint scheme used on ships, extensively during World War I and to a lesser extent in World War II. In a 1919 lecture, artist Norman Wilkinson explained: "The primary object of this scheme was not so much to cause the enemy to miss his shot when actually in firing position, but to mislead him, when the ship was first sighted, as to the correct position to take up. [Dazzle was a] method to produce an effect by paint in such a way that all accepted forms of a ship are broken up by masses of strongly contrasted colour, consequently making it a matter of difficulty for a submarine to decide on the exact course of the vessel to be attacked.... The colours mostly in use were black, white, blue and green.... When making a design for a vessel, vertical lines were largely avoided. Sloping lines, curves and stripes are by far the best and give greater distortion."

Image
HMAS Yarra in dazzle camouflage while sailing in the Persian Gulf – August 1941.

At first glance it seems unlikely camouflage, drawing attention to the ship rather than hiding it, but this technique was developed after the Allied Navy's failure to develop effective means to disguise ships in all weather. Dazzle did not conceal the ship but made it difficult for the enemy to estimate its speed and heading. The idea was to disrupt the visual rangefinders used for naval artillery. Its purpose was confusion rather than concealment. An observer would find it difficult to know exactly whether the stern or the bow is in view; and it would be equally difficult to estimate whether the observed vessel is moving towards or away from the observer's position.

The rangefinders were based on the co-incidence principle with an optical mechanism, operated by a human to compute the range. The operator adjusted the mechanism until two half-images of the target lined up in a complete picture. Dazzle was intended to make that hard because clashing patterns looked abnormal even when the two halves were aligned. This became more important when submarine periscopes included similar rangefinders. As an additional feature, the dazzle pattern usually included a false bow wave to make estimation of the ship's speed difficult.

All British patterns were different, first tested on small wooden models viewed through a periscope in a studio. Most of the model designs were painted by women from London's Royal Academy of Arts. A foreman then scaled up their designs for the real thing. Painters, however, were not alone in the project. Creative people including sculptors, abstract artists, and set designers designed camouflage.

American naval leadership thought dazzle effective. In 1918, the U.S. Navy adopted it, as one of several techniques. However effective the scheme was in World War I, it became less useful as rangefinders and especially aircraft became more advanced, and, by the time it was put to use again in World War II, radar further reduced its effectiveness. However, it may still have confounded submarines. Dazzle's effectiveness is not certain. The British Admiralty concluded it had no effect on submarine attacks, but proved to be a morale boost for crews. It also increased the morale of people not involved in fighting; hundreds of wonderfully coloured ships in dock was nothing ever seen before or since. Winston Churchill considered deception in war to be an indispensable "element of léger de main, an original and sinister touch, which leaves the enemy puzzled as well as beaten.">>

Re: 4 October 2009 Same Colour Illusion

by DavidLeodis » Mon Oct 05, 2009 1:25 pm

bystander wrote:
DavidLeodis wrote:Is there a particular reason why the green cylinder is there (assuming it is green and not an illusion! :) ) as the illusion works without it. :?:
To supply the shadow, without which there is no illusion. As to why it's green :?: I suppose any non-grey scale color would work.
Thanks bystander. So the illusion will still work if the cylinder was removed but the faint shadow was retained. The illusion is excellent and just seems improbable at first, and even more, looks. Making a printout and cutting squares is the best way I find to be definitely sure they are the same shade. Illusions are so confusing. Well they are at least to me! :)

Re: 4 October 2009 Same Colour Illusion

by bystander » Mon Oct 05, 2009 12:52 pm

DavidLeodis wrote:Is there a particular reason why the green cylinder is there (assuming it is green and not an illusion! :) ) as the illusion works without it. :?:
To supply the shadow, without which there is no illusion. As to why it's green :?: I suppose any non-grey scale color would work.

Re: 4 October 2009 Same Colour Illusion

by DavidLeodis » Mon Oct 05, 2009 11:43 am

Is there a particular reason why the green cylinder is there (assuming it is green and not an illusion! :) ) as the illusion works without it. :?:

Re: 4 October 2009 Same Colour Illusion

by neufer » Mon Oct 05, 2009 2:03 am

Rob_K wrote:Nice illusion & seen many times before, but tried something new with it.

Head sideways, cross eyes, move square A over square B, and run them around a little so there's a bit of overlap.
Warning: This procedure is not recommended if you are pregnant,
planning to become pregnant, or could become pregnant during this procedure.

Re: 4 October 2009 Same Colour Illusion

by Rob_K » Mon Oct 05, 2009 12:17 am

Nice illusion & seen many times before, but tried something new with it. Head sideways, cross eyes, move square A over square B, and run them around a little so there's a bit of overlap. Voila, the illusion is maintained, at least in my eyes!! One dark, one bright - any explanations? (optical please, I know that they're the same). :)

Cheers -

Rob

Re: 4 October 2009 Same Colour Illusion

by neufer » Sun Oct 04, 2009 10:23 pm

readm wrote:Small point: you could have also seen this same APOD on July 17, 2007
So the illusion is time invariant.

Re: 4 October 2009 Same Colour Illusion

by readm » Sun Oct 04, 2009 10:19 pm

Small point: you could have also seen this same APOD on July 17, 2007

Re: 4 October 2009 Same Colour Illusion

by neufer » Sun Oct 04, 2009 10:10 pm

Hugh wrote:The only confusion is over the term color.
There seems to be some confusion over the spelling as well. :wink:
http://en.wikipedia.org/wiki/American_and_British_English_spelling_differences#-our.2C_-or wrote:
<<Most words ending in an unstressed -our in the United Kingdom and Australia (e.g., colour, flavour, honour, neighbour, rumour, labour) end in -or in the United States (e.g., color, flavor, honor, neighbor, rumor, labor). Wherever the vowel is unreduced in pronunciation, this does not occur: contour, velour, paramour, troubadour, are spelled thus the same everywhere, with "contour" being an important technical term in mathematics and meteorology. Most words of this category derive from Latin non-agent nouns having nominative -or; the first such borrowings into English were from early Old French and the ending was -or or -ur. After the Norman Conquest, the termination became -our in Anglo-French in an attempt to represent the Old French pronunciation of words ending in -or, though color has been used occasionally in English since the fifteenth century. The -our ending was not only retained in English borrowings from Anglo-French, but also applied to earlier French borrowings. After the Renaissance, some such borrowings from Latin were taken up with their original -or termination; many words once ending in -our (for example, chancellour and governour) now end in -or everywhere. Many words of the -our/-or group do not have a Latin counterpart; for example, armo(u)r, behavio(u)r, harbo(u)r, neighbo(u)r; also arbo(u)r meaning "shelter", though senses "tree" and "tool" are always arbor, a false cognate of the other word.

Some 16th and early 17th century British scholars indeed insisted that -or be used for words of Latin origin (e.g. color) and -our for French loans; but in many cases the etymology was not completely clear, and therefore some scholars advocated -or only and others -our only.

Webster's 1828 dictionary featured only -or and is generally given much of the credit for the adoption of this form in the United States. By contrast, Dr Johnson's 1755 dictionary used the -our spelling for all words still so spelled in Britain, as well as for emperour, errour, governour, horrour, tenour, terrour, and tremour, where the u has since been dropped. Johnson, unlike Webster, was not an advocate of spelling reform, but selected the version best-derived, as he saw it, from among the variations in his sources: he favoured French over Latin spellings because, as he put it, "the French generally supplied us." Those English speakers who began to move across the Atlantic would have taken these habits with them and H L Mencken makes the point that, "honor appears in the Declaration of Independence, but it seems to have got there rather by accident than by design. In Jefferson’s original draft it is spelled honour." Examples such as color, flavor, behavior, harbor, or neighbor scarcely appear in the Old Bailey's court records from the 17th and 18th century, whereas examples of their -our counterparts are numbered in thousands. One notable exception is honor: honor and honour were equally frequent down to the 17th century, Honor still is, in the U.K., the normal spelling as a person's name.

Derivatives and inflected forms. In derivatives and inflected forms of the -our/or words, in British usage the u is kept before English suffixes that are freely attachable to English words (neighbourhood, humourless, savoury) and suffixes of Greek or Latin origin that have been naturalized (favourite, honourable, behaviourism); before Latin suffixes that are not freely attachable to English words, the u can be dropped (honorific, honorist, vigorous, humorous, laborious, invigorate), can be either dropped or retained (colo(u)ration, colo(u)rize), or can be retained (colourist). In American usage, derivatives and inflected forms are built by simply adding the suffix in all environments (favorite, savory, etc.) since the u is absent to begin with.

Exceptions. American usage in most cases retains the u in the word glamour, which comes from Scots, not Latin or French. "Glamor" is occasionally used in imitation of the spelling reform of other -our words to -or. The adjective "glamorous" omits the first "u". Saviour is a somewhat common variant of savior in the United States. The British spelling is very common for "honour" (and "favour") in the stilted language of wedding invitations in the United States. The name of the Space Shuttle Endeavour has a u in it since this spacecraft was named for Captain James Cook's ship, the HMS Endeavour.

The name of the herb savory is thus spelled everywhere, although the probably related adjective savo(u)ry, like savour, has a u in the U.K.. Honor (the name) and arbor (the tool) have -or in Britain, as mentioned above. As a general noun, rigour (/ˈrɪɡər/) has a u in the U.K.; the medical term rigor (often pronounced /ˈraɪɡɔr/) does not. Words with the ending -irior, -erior or similar are spelled thus everywhere and have never had a "u", for example inferior or exterior.

Commonwealth usage. Commonwealth countries normally follow British usage. In Canada -or endings are not uncommon, particularly in the Prairie Provinces, though they are rarer in Eastern Canada. In Australia, -or terminations enjoyed some use in the 19th century, and now are sporadically found in some regions, usually in local and regional newspapers, though -our is almost universal. The name of the Australian Labor Party, founded in 1891, is a remnant of this trend.

New Zealand English (e.g., Carl Horn) , while sharing some words and syntax with Australian English, follows British usage.>>

Re: 4 October 2009 Same Colour Illusion

by Hugh » Sun Oct 04, 2009 8:09 pm

Kevin and Jerry explain the "color" illusion well. The only confusion is over the term color. Jerry's use of the term "brightness" is more accurate than "color" in this case as it expresses the amount of light or dark to the eye as opposed to the amount ("intensity") of redness or blueness which is what we think of as color. The import of using the term "brightness" is that it can help in further explaining that the illusion, in this case, is a function of the eye chemistry as influenced by the adjacent brightness. Because the B square is surrounded by darker squares (than the A square's surround) it appears that the B square is brighter.
"Color" becomes a useful term when discussing other types of illusions: Say if you surround square "B" with Red, what color would square "B" appear?

Re: 4 October 2009 Same Colour Illusion

by Storm_norm » Sun Oct 04, 2009 4:03 pm

I guess its only truthful and factual to point out that illusions do exist when looking at the sky with the naked eye/through a telescope, etc... and I guess its only logical to NOT misinterpret these illusions so as to better understand our surroundings.

I am thankful, nonetheless, that knowing the truth behind these illusions does not take away my amazement at just how large that full moon looks on the horizon, or how twinkly those stars look peering down on me, or how orange and calm the sun looks at sunset veiled in whispy clouds. forgetting the truth in these cases is sweet bliss on my eyes.

however,

knowing that we can find out the truth behind these illusions is sometimes equally as bliss.

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