Visual Ilusions

**Albacore** · 28 August 2005, 09:32 AM

You have all seen these pictures that make scambled eggs of your eyeballs when you look at them too long. Just found this site which has 50 of them in the same place, http://www.michaelbach.de/ot/index.html

Well I thought some of them were really quite clever and worth a look.

**Grafixman** · 29 August 2005, 03:06 AM

Cool find. I just bookmarked it. Thanks

.
The motion induced blindness is very interesting. Makes one think of the dangers when driving. So there is the real danger of having cars in front suddenly disappear from view... Funny thing is that the dots don't disappear if you made them larger. Maybe that explains why people tend to stick close to the car in front

.

**Ross Macintosh** · 29 August 2005, 10:36 AM

Hmm... They still disappeared when I made them larger. That illusion must have to do with the regularity of the spinning pattern. I don't know if it explains anything about driving but maybe it does about quality control? Imagine a frenchfry factor and all the fries on a conveyor passing a worker whose job it is to pick out the bad ones. The regularity of the pattern they see might make them occassionally blind to some bad ones. Perhaps that's why there's always a few bad ones in the bag of frozen fries?

That is a great site Albacore! I've put a bookmark on my desktop hoping the kids will go there (and learn something) instead of their usual game sites.

I attach an ilusion I saw on another forum.

Regards, Ross

**Grafixman** · 29 August 2005, 02:07 PM

You got a point there, Ross. Usually too much distraction on the road for the effect to be effective. Quality control and people doing repetitive tasks are more likely to experience it.
That is a queer puzzle.

So the area remains the same even if one square is missing? Somebody explain it fast or it's going to dance inside my head all night....

Looking at it for a few more minutes, I guess that the hypotenuse of the two triangles (the larger and the smaller one), doesn't line up straight, although it may seem so. Thus you couldn't compute the total area of the triangle on the top as a single triangle. There is a slight deviation on the grid from the top and bottom pics along the diagonal edge.... perhaps they add up to the area of the missing block...

**RTK** · 29 August 2005, 08:08 PM

Hmmm.... trickery?

The images ares not real triangles? The top edge is slightly curved - the red and green shapes are curved. Changing places with the green and red extends the slope (angle) in the area where the remaning blocks need to fit in? I'm sure there is math involved explaining this kinds of things, but I'm just looking at it as a "picture".

Heck, this happens all the time when I draw my shapes...

Albacore - great link!

**Ross Macintosh** · 29 August 2005, 08:23 PM

Risto -- I don't think there are any curves. Print it out and cut out the pieces...

**RTK** · 29 August 2005, 08:40 PM

Ok, it should have said "curved" and "curves"...

The red and green shapes have different "angles". (Adding these " "" " all over the place now, just to be safe...)

See attached... Take in you images in to Xara X and draw a line on the edge of the triange and you will see that the two shapes don't make a real triangle. You can also see it from the grid pattern as Grafixman mentioned (which helped).

**RTK** · 29 August 2005, 08:48 PM

Looking at where the top edge runs through on the grid... If the two shapes had the same angle they would intersect the same "points" (

) on the grid in both images - no matter which way you put them.

**Ross Macintosh** · 29 August 2005, 09:16 PM

True enough my curvature-detecting buddy! Ah, but does that explain the missing square?

**RTK** · 29 August 2005, 09:31 PM

Yes it does... The angle of the red shape is less steep. When placed on the right-hand side it makes the right-hand side of the "faux triangle" longer/more volume - where the other shapes have to fit in - the green shape on the left just finishes of the "faux triangle".

You can see it from the grid.