[Gathnet] Re: Optical illusion of motion

[Barbara McClatchey]

One interesting aspect of this is that if you leave some "white space" at
the top of the picture and unfocus your eyes but aiming them toward the
white space just above the picture, you can have more than one wheel in
motion at the same time.  They appear to work like gears, moving in opposite
directions.  I've not been able to get more than three wheels into motion at
once, though it can probably be done if your focus is right.

Barbara McClatchey, SECOND CHANCE POMS, INC.
Lake Jackson, TX
Rescue at secondchancepoms.org or udxpom at yahoo.com
http://www.secondchancepoms.org
If you breed, rescue; if you don't breed, rescue anyway.

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----- Original Message ----- 
From: "SKM" <eyedoc7kids at cox.net>
To: "Gathnet" <gathnet at bmsi.com>; "Barbara McClatchey" <bclatch at mastnet.net>
Sent: Friday, July 02, 2004 6:31 AM
Subject: Optical illusion of motion


> http://www.cs.toronto.edu/~moraes/illusion.html
>
> I do not know how it works, but I will bet that it is related in part to
> the color of the ovals. If you think of this as a collection of segments
> consisting of two ovals (blue and yellow) with a connecting black
> biconcave lens, all the circles appear to rotate "away from yellow" and
> "towards the blue". If you convert the picture to grayscale, the
> illusion is still present but less strong. If you rotate the image 180
> degrees, the blue and yellow circles are on opposite sides, but the
> rules just mentioned apply. If you make it a "negative" (inverting all
> colors) these rules still apply. You can see this things yourself by
> saving the picture from your browser to your desktop and then
> manipulating it with a utility such as Irfan view.
>
> There is an explanation that I do not understand at
> http://psych.upenn.edu/backuslab/vss/vss2004/backus2004.html
> Scott
>
>