The hologram effect

[fawk3s]

http://static.howstuffworks.com/gif/hologram-6.gif
"If you tear a hologram in half, you can still see the whole image in each piece. The same is true with smaller and smaller pieces."

I dont understand how this works. Can anyone explain?

Thanks in advance,
fawk3s

[JDługosz]

Look at the original unbroken one. Cover up half of it. Turn the glass so you see "around" the mask. Cutting off the masked part is the same thing. The illustration is not very good; the piece edges don't show the same tilting as the image! I saw it "live" on an episode of NOVA and it was obvious.

--John