optical illusions explained

[Farsight]

Check out the Big Spanish Castle illusion at:

http://www.johnsadowski.com/big_spanish_castle.php

When I first saw this I just couldn't believe it. It's mind-blowingly good. Says something about consciousness and perception I suppose.

Edit: good couple of videos. Good bloke is Beau Lotto. He really got me thinking about the difference between observation and reality back in 2007. Oddly enough, there's a knack to this. With practice you learn to see what's there, and the "context" colour illusions don't work any more. I put my hand up when he asked if the two greys were the same. He did say that artists learn this, but I can't see it on his website any more: http://www.lottolab.org/. However the desert illusion still works, it's retinal, like the Big Spanish Castle.

 

[alfaniner]

That red-green/mountain illusion has virtually no effect on someone who is RG color-blind.

My favorite is the Mr. Angry/Ms. Calm picture (posted previously elsewhere).

As far as this discussion goes, I'm so glad that what's-his-name is no longer around (was it Itneresting Ian?)

 

[r-j]

I don't know how you interpret the picture, but I thought the whole point of the illusion was that squares of the same shade look lighter in the shadow.

It's more complicated than that. The checkerboard pattern is what causes the illusion, the dark squares around B, and the light squares around A.

 

[CORed]

Wright is no idiot, and surprisingly accessible to skeptics. My favourite:

"I have telekenetic powers. I can make coins come up heads. I can do it pretty consistently. Works about half the time."

My favorite is "Everyone who believes in telekinesis, raise my hand."

 

[MattTheTubaGuy]

I love those TED videos.

interesting at the end with the purple and yellow.

"Works about half the time."

 

[Deneb]

The claim we can read passages with the letters left out has been debunked. You can read some passages with letters left out, but there are many similarly adulterated passages which are not easily read.

In languages that are written using Arabic script (or variations thereof), vowels other than the long vowels (represented by [alif] ا, [yaa] ي and [waaw] و) are indicated using diacritical marks. However, these are generally dropped in everything except religious texts and works intended for beginners.

Given this, a sentence such as: "The cat is on the chair" (القط على الكرسي) which is:

Al qitou 3ala al koursiiyi

Is written as:

Al qt 3la al krsy

It's somewhat daunting at first, but most people who are familiar with the written forms of these languages don't seem to have too much trouble dealing with it.