Here's a cool optical illusion I saw once. It may be difficult to explain so please read carefully as I describe it..

I was driving east on a highway beside an airport. There were a row of trees between the highway and the runway. A plane ( traveling westward ) was making a landing on the runway. As I looked to my left I could see a the trees bluring by me ( actually I was moving past them ) and the fact that they seemed to be travelling westward very rapidly made the plane ( above and behind them ) seem to not move at all. I stared at it several times and is seemed to be stuck in mid air or almost moving backward. I suspect its the same effect as a full moon that seems to follow you as you drive but you are used to the moom being stationary. When you see a plane pointed west and slowly drifting east or remaining stationary in the air its freaky.

Nathan

Yes I have experienced this a lot while working on a base, seeing planes landing while going to lunch in a bus. I had no need for trees in my visual field to see them standing still in the air you know

Here's another "illusion" related to planes that makes you realize how often you're wrong when you're not used to long distances etc.. :

- When you hear a plane in the sky look at it a few seconds
- Now look down for ten seconds
- Now look where you think the plane is...

Normally, you'll be incredibly wrong, expecting to see it far far ahead from its actual position : somehow you expect it to move far faster in your visual field, it seems intuition does not make the speed/depth ratio and just take into account the speed. Yet another "proof" that we've got a 'limit depth' in our brain ? (see my other post "the pointer illusion" in this forum)...

I just found a book, "Visual Illusions," by Al Seckel, at Waldenbooks on clearance for $5.99. It has most of the classics and several that I have never seen before. It is a pretty good book. A couple of the photos show Jerry Andrus and also an unnamed individual who I am sure is The Amazing Randi. It's a good buy for the money.